Ion implantation apparatus

ABSTRACT

An ion implantation apparatus includes a scanning unit scanning the ion beams in a horizontal direction perpendicular to the reference trajectory and a downstream electrode device disposed downstream of the scanning electrode device. The scanning electrode device includes a pair of scanning electrodes disposed to face each other in the horizontal direction with the reference trajectory interposed therebetween. The downstream electrode device includes an electrode body configured such that, with respect to an opening width in a vertical direction perpendicular to both the reference trajectory and the horizontal direction and/or an opening thickness in a direction along the reference trajectory, the opening width and/or the opening thickness in a central portion in which the reference trajectory is disposed is different from the opening width and/or the opening thickness in the vicinity of a position facing the downstream end of the scanning electrode.

RELATED APPLICATION

Priority is claimed to Japanese Patent Application No. 2014-108008,filed on May 26, 2014, the entire content of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ion implantation apparatus.

2. Description of the Related Art

In a certain ion implantation apparatus, an ion source is connected to apower supply thereof such that an ion beam having a small amount of beamcurrent is extracted from the ion source. In this apparatus, theconnection between the ion source and the power supply may be modifiedsuch that an ion beam having a large amount of beam current is extractedfrom the ion source.

Another ion implantation apparatus includes an ion source, anacceleration tube, and an electric circuit connecting power suppliesthereof, so as to implant ions into a target at high ion energy. Theelectric circuit is provided with a selector switch for switching theconnection so as to implant ions at low ion energy.

Attempts to extend the operating range of the ion implantation apparatusto some degree have been made as described above. However, a realisticproposal to the extension of the operating range beyond the existingcategories is rare.

Generally, ion implantation apparatuses are classified into threecategories: a high-current ion implantation apparatus, a medium-currention implantation apparatus, and a high-energy ion implantationapparatus. Since practical design requirements are different for eachcategory, an apparatus of one category and an apparatus of anothercategory may have significantly different configurations in, forexample, beamline. Therefore, in the use of the ion implantationapparatus (for example, in a semiconductor manufacturing process), it isconsidered that apparatuses of different categories have nocompatibility. That is, for particular ion implantation processing, anapparatus of a particular category is selected and used. Therefore, fora variety of ion implantation processing, it is necessary to own varioustypes of ion implantation apparatuses.

SUMMARY OF THE INVENTION

An exemplary object of an aspect of the present invention is to providean ion implantation apparatus and an ion implantation method which canbe used in a wide range, for example, an ion implantation apparatuswhich can serve as both a high-current ion implantation apparatus and amedium-current ion implantation apparatus, and an ion implantationmethod.

According to an aspect of the present invention, there is provided anion implantation apparatus including a scanning unit, the scanning unitincluding a scanning electrode device that allows a deflecting electricfield to act on an ion beam incident along a reference trajectory andscans the ion beam in a horizontal direction perpendicular to thereference trajectory, and a downstream electrode device disposeddownstream of the scanning electrode device and provided with openingsthrough which the ion beam scanned in the horizontal direction passes,wherein the scanning electrode device includes a pair of scanningelectrodes disposed to face each other in the horizontal direction withthe reference trajectory interposed therebetween. The downstreamelectrode device includes an electrode body configured such that, withrespect to an opening width in a vertical direction perpendicular toboth the reference trajectory and the horizontal direction and/or anopening thickness in a direction along the reference trajectory, theopening width and/or the opening thickness in a central portion in whichthe reference trajectory is disposed is different from the opening widthand/or the opening thickness in the vicinity of a position facing thedownstream end of the scanning electrode.

Also, while arbitrary combinations of the above components or thecomponents or representations of the present invention are mutuallysubstituted among methods, apparatuses, systems, and programs, these arealso effective as the aspects of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating ranges of an energy and adose amount in several types of typical ion implantation apparatuses;

FIG. 2 is a diagram schematically illustrating an ion implantationapparatus according to an embodiment of the present invention;

FIG. 3 is a diagram schematically illustrating an ion implantationapparatus according to an embodiment of the present invention;

FIG. 4 is a flowchart illustrating an ion implantation method accordingto an embodiment of the present invention;

FIG. 5A is a plan view illustrating a schematic configuration of an ionimplantation apparatus according to an embodiment of the presentinvention, and FIG. 5B is a side view illustrating a schematicconfiguration of an ion implantation apparatus according to anembodiment of the present invention;

FIG. 6 is a diagram schematically illustrating a configuration of apower supply of an ion implantation apparatus according to an embodimentof the present invention;

FIG. 7 is a diagram schematically illustrating a configuration of apower supply of an ion implantation apparatus according to an embodimentof the present invention;

FIG. 8A is a diagram illustrating a voltage in an ion implantationapparatus according to an embodiment of the present invention, and FIG.8B is a diagram illustrating an energy in an ion implantation apparatusaccording to an embodiment of the present invention;

FIG. 9A is a diagram illustrating a voltage in an ion implantationapparatus according to an embodiment of the present invention, and FIG.9B is a diagram illustrating an energy in an ion implantation apparatusaccording to an embodiment of the present invention;

FIG. 10 is a flowchart illustrating an ion implantation method accordingto an embodiment of the present invention;

FIG. 11 is a diagram schematically illustrating ranges of an energy anda dose amount in an ion implantation apparatuses according to anembodiment of the present invention;

FIG. 12 is a diagram schematically illustrating ranges of an energy anda dose amount in an ion implantation apparatuses according to anembodiment of the present invention;

FIG. 13 is a diagram describing the use of a typical ion implantationapparatus;

FIG. 14 is a diagram describing the use of an ion implantation apparatusaccording to an embodiment of the present invention;

FIG. 15 is a perspective cross-sectional view illustrating aconfiguration of a scanning unit included in anion implantationapparatus according to an embodiment of the present invention;

FIGS. 16A and 16B are cross-sectional views schematically illustrating aconfiguration of an upstream electrode device, a scanning electrodedevice, and a downstream electrode device illustrated in FIG. 15;

FIG. 17 is a diagram schematically illustrating a configuration of ascanning electrode device;

FIGS. 18A and 18B are diagrams schematically illustrating a shape of afirst upstream reference voltage electrode;

FIGS. 19A and 19B are diagrams schematically illustrating trajectoriesof ion beams passing through a first upstream reference voltageelectrode and a scanning electrode device according to a comparativeexample;

FIGS. 20A and 20B are diagrams schematically illustrating trajectoriesof ion beams passing through a first upstream reference voltageelectrode and a scanning electrode device according to the comparativeexample;

FIGS. 21A and 21B are diagrams schematically illustrating trajectoriesof ion beams passing through a first upstream reference voltageelectrode and a scanning electrode device according to an embodiment ofthe present invention;

FIGS. 22A and 22B are diagrams schematically illustrating trajectoriesof ion beams passing through a first upstream reference voltageelectrode and a scanning electrode device according to an embodiment ofthe present invention;

FIGS. 23A and 23B are diagrams schematically illustrating trajectoriesof ion beams passing through a first upstream reference voltageelectrode and a scanning electrode device according to an embodiment ofthe present invention;

FIGS. 24A and 24B are diagrams schematically illustrating a shape of abeam transport correction electrode according to a modification;

FIG. 25 is a diagram schematically illustrating trajectories of ionbeams passing through a first upstream reference voltage electrode and ascanning electrode device according to a modification;

FIG. 26 is a diagram schematically illustrating trajectories of ionbeams passing through a first upstream reference voltage electrode and ascanning electrode device according to a modification;

FIGS. 27A and 27B are diagrams schematically illustrating a shape of afirst downstream reference voltage electrode;

FIG. 28 is a diagram schematically illustrating a structure of a firstdownstream reference voltage electrode and a first downstreamintermediate electrode;

FIG. 29 is a diagram schematically illustrating trajectories of ionbeams passing through a first downstream reference voltage electrode anda first downstream intermediate electrode according to the comparativeexample;

FIG. 30 is a diagram schematically illustrating a shape of a firstdownstream reference voltage electrode according to the comparativeexample;

FIG. 31 is a diagram schematically illustrating trajectories of ionbeams passing through a scanning electrode device, a first downstreamreference voltage electrode, and a first downstream intermediateelectrode according to an embodiment of the present invention;

FIG. 32 is a diagram schematically illustrating trajectories of ionbeams passing through a scanning electrode device, a first downstreamreference voltage electrode, and a downstream first intermediateelectrode according to an embodiment of the present invention;

FIG. 33 is a diagram schematically illustrating a shape of a firstdownstream reference voltage electrode and a first downstreamintermediate electrode according to a modification;

FIGS. 34A and 34B schematically illustrate a trajectory of ion beamspassing through an upstream electrode device and a scanning electrodedevice according to an embodiment of the present invention; and

FIGS. 35A, 35B, and 35C are diagrams schematically illustrating aconfiguration of an upstream electrode device and a scanning electrodedevice according to a modification.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described by reference to the preferredembodiments. This does not intend to limit the scope of the presentinvention, but to exemplify the invention.

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. Also, in the description of thedrawings, the same reference numerals are assigned to the samecomponents, and a redundant description thereof is appropriatelyomitted. Also, the configurations described below are exemplary, and donot limit the scope of the present invention. For example, in thefollowing, a semiconductor wafer is described as an example of an objectto which an ion implantation is performed, but other materials ormembers may also be used.

First, a description will be given of circumstances that led to anembodiment of the present invention to be described below. An ionimplantation apparatus can select an ion species to be implanted and setan energy and a dose amount thereof, based on desired properties to beestablished within a workpiece. Generally, ion implantation apparatusesare classified into several categories according to the ranges of energyand dose amount of ions to be implanted. As representative categories,there are a high-dose high-current ion implantation apparatus(hereinafter, referred to as HC), a medium-dose medium-current ionimplantation apparatus (hereinafter, referred to as MC), and ahigh-energy ion implantation apparatus (hereinafter, referred to as HE).

FIG. 1 schematically illustrates the energy ranges and the dose rangesof a typical serial-type high-dose high-current ion implantationapparatus HC, a serial-type medium-dose medium-current ion implantationapparatus MC, and a serial-type high-energy ion implantation apparatusHE. In FIG. 1, a horizontal axis represents the dose, and a verticalaxis represents the energy. The dose is the number of ions (atoms)implanted per unit area (for example, cm²), and the total amount ofimplanted material is provided by a time integral of ion current. Theion current provided by the ion implantation is generally expressed asmA or μA. The dose is also referred to as an implantation amount or adose amount. In FIG. 1, the energy and dose ranges of the HC, the MC,and the HE are indicated by symbols A, B, and C, respectively. These area set range of implantation conditions required according toimplantation conditions (also called a recipe) for each implantation,and represent practically reasonable apparatus configuration categoriesmatched with the implantation conditions (recipe), consideringpractically allowable productivity. Each of the illustrated rangesrepresents an implantation condition (recipe) range that can beprocessed by the apparatus of each category. The dose amount representsan approximate value when a realistic processing time is assumed.

The HC is used for ion implantation in a relatively low energy range ofabout 0.1 to 100 keV and in a high dose range of about 1×10¹⁴ to 1×10¹⁷atoms/cm². The MC is used for ion implantation in a medium energy rangeof about 3 to 500 keV and in a medium dose range of about 1×10¹¹ to1×10¹⁴ atoms/cm². The HE is used for ion implantation in a relativelyhigh energy range of about 100 keV to 5 MeV and in a relatively low doserange of about 1×10¹⁰ to 1×10¹³ atoms/cm². In this way, the broad rangesof the implantation conditions having about five digits for the energyrange and about seven digits for the dose ranges are shared by the HC,the MC, and the HE. However, these energy ranges or dose ranges are arepresentative example, and are not strict. Also, the way of providingthe implantation conditions is not limited to the dose and the energy,but is various. The implantation conditions may be set by a beam currentvalue (representing an area integral beam amount of a beamcross-sectional profile by a current), a throughput, implantationuniformity, and the like.

Since the implantation conditions for ion implantation processinginclude particular values of energy and dose, the implantationconditions can be expressed as individual points in FIG. 1. For example,an implantation condition a has values of a high energy and a low dose.The implantation condition a is in the operating range of the MC and isalso in the operating range of the HE. The ion implantation can beprocessed accordingly using the MC or the HE. An implantation conditionb is a medium energy/dose and the ion implantation can be processed byone of the HC, MC, and HE. An implantation condition c is a mediumenergy/dose and the ion implantation can be processed by the HC or theMC. An implantation condition d is a low energy/a high dose and can beprocessed by only the HC.

The ion implantation apparatus is an equipment essential to theproduction of semiconductor devices, and the improvement of performanceand productivity thereof has an important meaning to a device maker. Thedevice maker selects an apparatus, which is capable of realizingimplantation characteristics necessary for a device to be manufactured,among a plurality of ion implantation apparatus categories. At thistime, the device maker determines the number of apparatuses of thecategory, considering various circumstances such as the realization ofthe best manufacturing efficiency, the cost of ownership of theapparatus, and the like.

It is assumed that an apparatus of a certain category is used at a highoperating rate and an apparatus of another category has a relativelysufficient processing capacity. At this time, if the former apparatuscannot be replaced with the latter apparatus in order to obtain adesired device because implantation characteristics are strictlydifferent for each category, the failure of the former apparatus cause abottleneck on production processes, and thus overall productivity isimpaired. Such trouble may be avoided to some extent by assuming afailure rate and the like in advance and determining a numberconfiguration based on that.

When a manufacturing device is changed due to a change in demand or atechnical advance and the number configuration of necessary apparatusesis changed, apparatuses become lacking or a non-operating apparatusoccurs and thus an operating efficiency of the apparatuses may bereduced. Such trouble may be avoided to some extent by predicting thetrend of future products and reflecting the predicted trend to thenumber configuration.

Even though the apparatus can be replaced with an apparatus of anothercategory, the failure of the apparatus or the change of themanufacturing device may reduce the production efficiency or lead towasted investment for the device maker. For example, in some cases, amanufacturing process having been mainly processed till now by amedium-current ion implantation apparatus is processed by a high-currention implantation apparatus due to the change of the manufacturingdevice. If doing so, the processing capacity of the high-current ionimplantation apparatus becomes lacking, and the processing capacity ofthe medium-current ion implantation apparatus becomes surplus. If it isexpected that the state after the change will not change for a longperiod of time, the operating efficiency of the apparatus can beimproved by taking measures of purchasing a new high-current ionimplantation apparatus and selling the medium-current ion implantationapparatus having been owned. However, when a process is frequentlychanged, or such a change is difficult to predict, a trouble may becaused in production.

In practice, a process having already been performed in an ionimplantation apparatus of a certain category in order to manufacture acertain device cannot be immediately used in an ion implantationapparatus of another category. This is because a process of matchingdevice characteristics on the ion implantation apparatus is required.That is, device characteristics obtained by performing a process withthe same ion species, energy, and dose amount in the new ionimplantation apparatus may be significantly different from devicecharacteristics obtained in the previous ion implantation apparatus.Various conditions other than the ion species, the energy, and the doseamount, for example, a beam current density (that is, a dose rate), animplantation angle, or an overspray method of an implantation region,also affect the device characteristics. Generally, when the categoriesare different, apparatus configurations also are different. Therefore,even though the ion species, the energy, and the dose amount arespecified, it is impossible to automatically match the other conditionsaffecting the device characteristics. These conditions depend onimplantation methods. Examples of the implantation methods include amethod of relative movement between a beam and a workpiece (for example,a scanning beam, a ribbon beam, a two-dimensional wafer scanning, or thelike), a batch type and a serial type to be described below.

In addition, rough classification of the high-dose high-current ionimplantation apparatus and the high-energy ion implantation apparatusinto a batch type and the medium-dose medium-current ion implantationapparatus into a serial type also increases a difference between theapparatuses. The batch type is a method of processing a plurality ofwafers at one time, and these wafers are disposed on, for example, thecircumference. The serial type is a method of processing wafers one byone and is also called a single wafer type. Also, in some cases, thehigh-dose high-current ion implantation apparatus and the high-energyion implantation apparatus are configured as the serial type.

Also, a beamline of the batch-type high-dose high-current ionimplantation apparatus is typically made shorter than that of theserial-type medium-dose medium-current ion implantation apparatus by arequest on beamline design according to high-dose high-current beamcharacteristics. This is done for suppressing beam loss caused bydivergence of ion beams in a low energy/high beam current condition inthe design of the high-dose high-current beamline. In particular, thisis done for reducing a tendency to expand outward in a radial direction,so-called a beam blow-up, because ions forming the beam include chargedparticles repelling each other. The necessity for such design is moreremarkable when the high-dose high-current ion implantation apparatus isthe batch type than when that is the serial type.

The beamline of the serial-type medium-dose medium-current ionimplantation apparatus is made relatively long for ion beam accelerationor beam forming. In the serial-type medium-dose medium-current ionimplantation apparatus, ions having considerable momentum are moving athigh speed. The momentum of the ions increases while the ions passthrough one or several of acceleration gaps added to the beamline. Also,in order to modify a trajectory of particles having considerablemomentum, a focusing portion needs to be relatively long enough to fullyapply a focusing power.

Since the high-energy ion implantation apparatus adopts a linearacceleration method or a tandem acceleration method, it is essentiallydifferent from an acceleration method of the high-dose high-current ionimplantation apparatus or the medium-dose medium-current ionimplantation apparatus. This essential difference is equally appliedwhen the high-energy ion implantation apparatus is the serial type orthe batch type.

As such, the ion implantation apparatuses HC, MC and HE are recognizedas completely different apparatuses because the beamline types or theimplantation methods are different according to categories. A differencein configuration between apparatuses of different categories isrecognized as inevitable. Among the different types of apparatuses suchas HC, MC and HE, process compatibility considering the influence on thedevice characteristics is not guaranteed.

Therefore, it is preferable that the ion implantation apparatus has abroader energy range and/or dose range than the apparatus of theexisting category. In particular, it is desirable to provide an ionimplantation apparatus capable of implantation in a broad range ofenergy and dose amount including at least two existing categories,without changing the type of the implantation apparatus.

Also, in recent years, the mainstream is that all implantationapparatuses adopt the serial type. It is therefore desirable to providean ion implantation apparatus that has a serial-type configuration andalso has a broad energy range and/or dose range.

Also, the HE uses an essentially different acceleration method, and theHC and the MC are common in that ion beams are accelerated ordecelerated by a DC voltage. Therefore, there is a probability that theHC and the MC can share the beamline. It is therefore desirable toprovide an ion implantation apparatus that can serve as both the HC andthe MC.

The apparatus capable of operating at a broad range helps to improveproductivity or operating efficiency in view of device makers.

Also, the medium-current ion implantation apparatus MC can operate in ahigh energy range and a low dose range as compared with the high-currention implantation apparatus HC. Therefore, in this application, themedium-current ion implantation apparatus MC is also referred to as alow-current ion implantation apparatus. Likewise, regarding themedium-current ion implantation apparatus MC, the energy and the doseare also referred to as high energy and low dose, respectively.Alternatively, regarding the high-current ion implantation apparatus HC,the energy and the dose are also referred to as low energy and highdose, respectively. However, these expressions in this application arenot intended to restrictively indicate only the energy range and thedose range of the medium-current ion implantation apparatus MC, but maymean “a high (or low) energy (or dose) range” literally according to thecontext.

FIG. 2 is a diagram schematically illustrating an ion implantationapparatus 100 according to an embodiment of the present invention. Theion implantation apparatus 100 is configured to perform ion implantationprocessing on a surface of a workpiece W according to given ionimplantation conditions. The ion implantation conditions include, forexample, an ion species to be implanted into the workpiece W, an iondose amount, and ion energy. The workpiece W is, for example, asubstrate, or, for example, a wafer. Therefore, in the following, theworkpiece W is also referred to as a substrate W for convenience ofdescription. This is not intended to limit a target of the implantationprocessing to a particular object.

The ion implantation apparatus 100 includes an ion source 102, abeamline device 104, and an implantation processing chamber 106. Also,the ion implantation apparatus 100 includes a vacuum exhaust system (notillustrated) for providing desired vacuum environments to the ion source102, the beamline device 104, and the implantation processing chamber106.

The ion source 102 is configured to generate ions to be implanted intothe substrate W. The ion source 102 provides the beamline device 104with an ion beam B1 accelerated and extracted from the ion source 102 byan extraction electrode unit 118 that is an example of a component foradjusting a beam current. Hereinafter, this may be also referred to asan initial ion beam B1.

The beamline device 104 is configured to transport ions from the ionsource 102 to the implantation processing chamber 106. The beamlinedevice 104 provides a beamline for transporting the ion beam. Thebeamline is a passage of the ion beam and may be also said as a path ofbeam trajectory. The beamline device 104 performs operations includingdeflection, acceleration, deceleration, shaping, and scanning, withrespect to the initial ion beam B1, thereby forming an ion beam B2.Hereinafter, this may be also referred to as an implantation ion beamB2. The beamline device 104 includes a plurality of beamline componentsarranged for such beam operations. In this manner, the beamline device104 provides the implantation processing chamber 106 with theimplantation ion beam B2.

The implantation ion beam B2 has a beam irradiation region 105 in theplane perpendicular to a beam transport direction (or a direction alonga beam trajectory) of the beamline device 104. Generally, the beamirradiation region 105 has a width including the width of the substrateW. For example, when the beamline device 104 includes a beam scanningdevice scanning a spot-shaped ion beam, the beam irradiation region 105is an elongated irradiation region extending over a scanning range alonga longitudinal direction perpendicular to the beam transport direction.Also, likewise, when the beamline device 104 includes a ribbon beamgenerator, the beam irradiation region 105 is an elongated irradiationregion extending in a longitudinal direction perpendicular to the beamtransport direction. However, the elongated irradiation region is across-section of a corresponding ribbon beam. The elongated irradiationregion is longer than the width (diameter when the substrate W iscircular) of the substrate W in a longitudinal direction.

The implantation processing chamber 106 includes a workpiece holder 107holding the substrate W such that the substrate W receives theimplantation ion beam B2. The workpiece holder 107 is configured to movethe substrate W in a direction perpendicular to the beam transportdirection of the beamline device 104 and the longitudinal direction ofthe beam irradiation region 105. That is, the workpiece holder 107provides a mechanical scan of the substrate W. In this application, themechanical scan is the same as reciprocating motion. Also, the“perpendicular direction” is not limited to only a strict right angle.For example, when the implantation is performed in a state in which thesubstrate W is inclined in a vertical direction, the “perpendiculardirection” may include such an inclined angle.

The implantation processing chamber 106 is configured as a serial-typeimplantation processing chamber. Therefore, the workpiece holder 107typically holds one sheet of the substrate W. However, like the batchtype, the workpiece holder 107 may include a support holding a pluralityof (for example, small) substrates, and may be configured tomechanically scan the plurality of substrates by linearly reciprocatingthe support. In another embodiment, the implantation processing chamber106 may be configured as a batch-type implantation processing chamber.In this case, for example, the workpiece holder 107 may include arotating disk that rotatably holds a plurality of substrates W on thecircumference of the disk. The rotating disk may be configured toprovide a mechanical scanning.

FIG. 3 illustrates an example of the beam irradiation region 105 and therelevant mechanical scanning. The ion implantation apparatus 100 isconfigured to perform ion implantation by a hybrid scanning method usingboth one-dimensional beam scanning S_(B) of the spot-shaped ion beam B2and one-dimensional mechanical scanning S_(M) of the substrate W. On theside of the workpiece holder 107, a beam measurement device 130 (forexample, Faraday cup) is provided to overlap the beam irradiation region105, and the measurement result may be provided to a control unit 116.

In this manner, the beamline device 104 is configured to supply theimplantation processing chamber 106 with the implantation ion beam B2having the beam irradiation region 105. The beam implantation region 105is formed to irradiate the implantation ion beam B2 across the substrateW in cooperation with the mechanical scanning of the substrate W.Therefore, ions can be implanted into the substrate W by the relativemovement of the substrate W and the ion beam.

In another embodiment, the ion implantation apparatus 100 is configuredto perform ion implantation by a ribbon beam+wafer scanning method usingboth the ribbon-shaped ion beam B2 and the one-dimensional mechanicalscanning of the substrate W. The horizontal width of the ribbon beam isexpanded while maintaining uniformity, and the substrate W is scanned soas to intersect with the ribbon beam. In a further embodiment, the ionimplantation apparatus 100 may be configured to perform ion implantationby a method of two-dimensionally mechanically scanning the substrate Win a state in which the beam trajectory of the spot-shaped ion beam B2is fixed.

Also, the ion implantation apparatus 100 is not limited to a particularimplantation method for implanting ions across a broad region on thesubstrate W. An implantation method using no mechanical scanning is alsopossible. For example, the ion implantation apparatus 100 may beconfigured to perform ion implantation by a two-dimensional beamscanning method of two-dimensionally scanning the substrate W with thespot-shaped ion beam B2. Alternatively, the ion implantation apparatus100 may be configured to perform ion implantation by a large-size beammethod using the two-dimensionally expanded ion beam B2. The large-sizebeam is expanded to make a beam size equal to or larger than a substratesize while maintaining uniformity, and can process the entire substrateat one time.

Although details will be described below, the ion implantation apparatus100 may be operated under a first beamline setting S1 for high-doseimplantation or a second beamline setting S2 for low-dose implantation.Therefore, the beamline device 104 has the first beamline setting S1 orthe second beamline setting S2 during operations. The two settings aredetermined to generate the ion beams for different ion implantationconditions under the common implantation method. Thus, in the firstbeamline setting S1 and the second beamline setting S2, the beam centertrajectories being the reference of the ion beams B1 and B2 areidentical to each other. The beam irradiation regions 105 are alsoidentical to each other in the first beamline setting S1 and the secondbeamline setting S2.

The beam center trajectory being the reference refers to a beamtrajectory when beam is not scanned in the beam scanning method. Also,in the case of the ribbon beam, the beam center trajectory being thereference corresponds to a locus of a geometric center of a beamcross-section.

The beamline device 104 may be divided into a beamline upstream part onthe ion source 102 side and a beamline downstream part on theimplantation processing chamber 106 side. In the beamline upstream part,for example, a mass spectrometer 108 including a mass analysis magnetand a mass analysis slit is provided. The mass spectrometer 108 performsmass spectrometry on the initial ion beam B1 and provides only necessaryion species to the beamline downstream part. In the beamline downstreampart, for example, a beam irradiation region determination unit 110 isprovided to determine the beam irradiation region 105 of theimplantation ion beam B2.

The beam irradiation region determination unit 110 is configured to emitthe ion beam having the beam irradiation region 105 (for example, theimplantation ion beam B2) by applying either (or both) of an electricfield and a magnetic field to the incident ion beam (for example, theinitial ion beam B1). In an embodiment, the beam irradiation regiondetermination unit 110 includes abeam scanning device and a beamparallelizing device. Examples of the beamline components will bedescribed below with reference to FIG. 5.

Also, it should be understood that the division into the upstream partand the downstream part, as above-described, is mentioned forconveniently describing a relative position relationship of thecomponents in the beamline device 104. Therefore, for example, acomponent in the beamline downstream part may be disposed at a placecloser to the ion source 102 than the position described above. Theopposite holds true as well. Therefore, in an embodiment, the beamirradiation region determination unit 110 may include a ribbon beamgenerator and a beam parallelizing device, and the ribbon beam generatormay include the mass spectrometer 108.

The beamline device 104 includes an energy adjustment system 112 and abeam current adjustment system 114. The energy adjustment system 112 isconfigured to adjust implantation energy to the substrate W. The beamcurrent adjustment system 114 is configured to adjust the beam currentin a broad range so as to change a dose amount implanted into thesubstrate W in a broad range. The beam current adjustment system 114 isprovided to adjust the beam current of the ion beam quantitatively(rather than qualitatively). In an embodiment, the adjustment of the ionsource 102 can be also used to adjust the beam current. In this case,the beam current adjustment system 114 may be considered to include theion source 102. Details of the energy adjustment system 112 and the beamcurrent adjustment system 114 will be described below.

Also, the ion implantation apparatus 100 includes a control unit 116 forcontrolling all or part of the ion implantation apparatus 100 (forexample, all or part of the beamline device 104). The control unit 116is configured to select any one from a plurality of beamline settingsincluding the first beamline setting S1 and the second beamline settingS2, and operate the beamline device 104 under the selected beamlinesetting. Specifically, the control unit 116 sets the energy adjustmentsystem 112 and the beam current adjustment system 114 according to theselected beamline setting, and controls the energy adjustment system 112and the beam current adjustment system 114. Also, the control unit 116may be a dedicated controller for controlling the energy adjustmentsystem 112 and the beam current adjustment system 114.

The control unit 116 is configured to select a beamline setting suitablefor given ion implantation conditions among the plurality of beamlinesettings including the first beamline setting S1 and the second beamlinesetting S2. The first beamline setting S1 is suitable for transport of ahigh-current beam for high-dose implantation into the substrate W.Therefore, for example, the control unit 116 selects the first beamlinesetting S1 when a desired ion dose amount implanted into the substrate Wis in the range of about 1×10¹⁴ to 1×10¹⁷ atoms/cm². Also, the secondbeamline setting S2 is suitable for transport of a low-current beam forlow-dose implantation into the substrate. Therefore, for example, thecontrol unit 116 selects the second beamline setting S2 when a desiredion dose amount implanted into the substrate W is in the range of about1×10¹¹ to 1×10¹⁴ atoms/cm². Details of the beamline settings will bedescribed below.

The energy adjustment system 112 includes a plurality of energyadjustment elements arranged along the beamline device 104. Theplurality of energy adjustment elements is disposed at fixed positionson the beamline device 104. As illustrated in FIG. 2, the energyadjustment system 112 includes, for example, three adjustment elements,specifically, an upstream adjustment element 118, an intermediateadjustment element 120, and a downstream adjustment element 122. Each ofthese adjustment elements includes one or more electrodes configured toexert an electric field for accelerating or decelerating the initial ionbeam B1 and/or the implantation ion beam B2.

The upstream adjustment element 118 is provided in the upstream part ofthe beamline device 104, for example, the most upstream part of thebeamline device 104. The upstream adjustment element 118 includes, forexample, an extraction electrode system for extracting the initial ionbeam B1 from the ion source 102 to the beamline device 104. Theintermediate adjustment element 120 is installed in the middle portionof the beamline device 104 and includes, for example, an electrostaticbeam parallelizing device. The downstream adjustment element 122 isprovided in the downstreampart of the beamline device 104 and includes,for example, an acceleration/deceleration column. The downstreamadjustment element 122 may include an angular energy filter (AEF)disposed in the downstream of the acceleration/deceleration column.

Also, the energy adjustment system 112 includes a power supply systemfor the above-described energy adjustment elements. This will bedescribed below with reference to FIGS. 6 and 7. Also, the plurality ofenergy adjustment elements may be provided in any number anywhere on thebeamline device 104, which is not limited to the illustratedarrangement. Also, the energy adjustment system 112 may include only oneenergy adjustment element.

The beam current adjustment system 114 is provided in the upstream partof the beamline device 104, and includes a beam current adjustmentelement 124 for adjusting the beam current of the initial ion beam B1.The beam current adjustment element 124 is configured to block at leasta portion of the initial ion beam B1 when the initial ion beam B1 passesthrough the beam current adjustment element 124. In an embodiment, thebeam current adjustment system 114 may include a plurality of currentadjustment elements 124 arranged along the beamline device 104. Also,the beam current adjustment system 114 may be provided in the downstreampart of the beamline device 104.

The beam current adjustment element 124 includes a movable portion foradjusting a passage region of the ion beam cross-section perpendicularto the beam transport direction of the beamline device 104. According tothe movable portion, the beam current adjustment element 124 constitutesa beam limiting device having a variable-width slit or a variable-shapeopening for limiting a portion of the initial ion beam B1. Also, thebeam current adjustment system 114 includes a driving device forcontinuously or discontinuously adjusting the movable portion of thebeam current adjustment element 124.

Additionally or alternatively, the beam current adjustment element 124may include a plurality of adjustment members (for example, adjustmentaperture) each having a plurality of beam passage regions havingdifferent areas and/or shapes. The beam current adjustment element 124may be configured to switch the adjustment member disposed on the beamtrajectory among the plurality of adjustment members. In this manner,the beam current adjustment element 124 may be configured to adjust thebeam current stepwise.

As illustrated, the beam current adjustment element 124 is a beamlinecomponent separate from the plurality of energy adjustment elements ofthe energy adjustment system 112. By separately installing the beamcurrent adjustment element and the energy adjustment element, the beamcurrent adjustment and the energy adjustment may be individuallyperformed. This may increase the degree of freedom in the setting of thebeam current range and the energy range in the individual beamlinesettings.

The first beamline setting S1 includes a first energy setting for theenergy adjustment system 112 and a first beam current setting for thebeam current adjustment system 114. The second beamline setting S2includes a second energy setting for the energy adjustment system 112and a second beam current setting for the beam current adjustment system114. The first beamline setting S1 is directed to the low-energy andhigh-dose ion implantation, and the second beamline setting S2 isdirected to the high-energy and low-dose ion implantation.

Therefore, the first energy setting is determined to be suitable for thetransport of the low-energy beam as compared with the second energysetting. Also, the second beam current setting is determined to reducethe beam current of the ion beam as compared with the first beam currentsetting. By combining the beam current adjustment and the irradiationtime adjustment of the implantation ion beam B2, a desired dose amountcan be implanted into the substrate W.

The first energy setting includes a first power supply connectionsetting that determines the connection between the energy adjustmentsystem 112 and the power supply system thereof. The second energysetting includes a second power supply connection setting thatdetermines the connection between the energy adjustment system 112 andthe power supply system thereof. The power supply connection settingsare determined such that the intermediate adjustment element 120 and/orthe downstream adjustment element 122 generate an electric field forhelping the beam transport. For example, the beam parallelizing deviceand/or the acceleration/deceleration column, as a whole, are configuredto decelerate the implantation ion beam B2 under the first energysetting and accelerate the implantation ion beam B2 under the secondenergy setting. Due to the power supply connection settings, a voltageadjustment range of each adjustment element of the energy adjustmentsystem 112 is determined. In the adjustment range, a voltage of thepower supply corresponding to each adjustment element can be adjusted toprovide a desired implantation energy to the implantation ion beam B2.

The first beam current setting includes a first opening setting thatdetermines the ion beam passage region of the beam current adjustmentelement 124. The second beam current setting includes a second openingsetting that determines the ion beam passage region of the beam currentadjustment element 124. The second opening setting is determined suchthat the ion beam passage region is small as compared with the firstopening setting. The opening settings determine, for example, themovable range of the movable portion of the beam current adjustmentelement 124. Alternatively, the opening settings may determine theadjustment member to be used. In this manner, the ion beam passageregion corresponding to the desired beam current within the adjustmentrange determined by the opening settings may be set to the beam currentadjustment element 124. The ion beam passage region can be adjusted suchthat a desired dose amount is implanted into the substrate W within aprocessing time permitted to the ion implantation processing.

Thus, the beamline device 104 has a first energy adjustment range underthe first beamline setting S1 and has a second energy adjustment rangeunder the second beamline setting S2. In order to enable a broad rangeof the adjustment, the first energy adjustment range has a portionoverlapping the second energy adjustment range. That is, two adjustmentranges overlap each other in at least the ends thereof. The overlappingportion may be a straight-line in the diagram schematically illustratingrange of an energy and dose of ion implantation apparatuses. In thiscase, two adjustment ranges contact each other. In another embodiment,the first energy adjustment range may be separated from the secondenergy adjustment range.

Likewise, the beamline device 104 has a first dose adjustment rangeunder the first beamline setting S1 and has a second dose adjustmentrange under the second beamline setting S2. The first dose adjustmentrange has a portion overlapping the second dose adjustment range. Thatis, two adjustment ranges overlap each other in at least the endsthereof. The overlapping portion may be a straight-line in the diagramschematically illustrating range of an energy and dose of ionimplantation apparatuses. In this case, two adjustment ranges contacteach other. In another embodiment, the first dose adjustment range maybe separated from the second dose adjustment range.

In this manner, the beamline device 104 is operated in a first operationmode under the first beamline setting S1. The first operation mode maybe referred to as a low-energy mode (or a high-dose mode). Also, thebeamline device 104 is operated in a second operation mode under thesecond beamline setting S2. The second operation mode may be referred toas a high-energy mode (or a low-dose mode). The first beamline settingS1 can be also referred to as a first implantation setting configurationsuitable for the transport of a low-energy/high-current beam for thehigh-dose implantation into the workpiece W. The second beamline settingS2 can be also referred to as a second implantation settingconfiguration suitable for the transport of a high-energy/low-currentbeam for the low-dose implantation into the workpiece W.

An operator of the ion implantation apparatus 100 can switch thebeamline settings before a certain ion implantation processing isperformed, depending on the implantation conditions of the processing.Therefore, the broad range from the low-energy (or high-dose) to thehigh-energy (or low-dose) can be processed by one ion implantationapparatus.

Also, the ion implantation apparatus 100 corresponds to the broad rangeof the implantation conditions in the same implantation method. That is,the ion implantation apparatus 100 processes abroad range withsubstantially the same beamline device 104. Also, the ion implantationapparatus 100 has the serial-type configuration that is recentlybecoming the mainstream. Therefore, although details will be describedbelow, the ion implantation apparatus 100 is suitable for use as ashared unit of the existing ion implantation apparatuses (for example,HC and MC).

The beamline device 104 can also be considered to include abeam controldevice for controlling the ion beam, a beam conditioning device forconditioning the ion beam, and a beam shaping device for shaping the ionbeam. The beamline device 104 supplies the ion beam having the beamirradiation region 105 exceeding the width of the workpiece W in theimplantation processing chamber 106 by using the beam control device,the beam conditioning device, and the beam shaping device. In the ionimplantation apparatus 100, the beam control device, the beamconditioning device, and the beam shaping device may have the samehardware configuration in the first beamline setting S1 and the secondbeamline setting S2. In this case, the beam control device, the beamconditioning device, and the beam shaping device may be disposed withthe same layout in the first beamline setting S1 and the second beamlinesetting S2. Therefore, the ion implantation apparatus 100 may have thesame installation floor area (so-called footprint) in the first beamlinesetting S1 and the second beamline setting S2.

The beam center trajectory being the reference is a beam trajectory thatis a locus of geometric center of the beam cross-section without beamscanning in the beam scanning method. Also, in the case of the ribbonbeam that is a stationary beam, the beam center trajectory being thereference corresponds to a locus of a geometric center of the beamcross-section, regardless of a change in the beam cross-sectional shapein the implantation ion beam B2 of the downstream part.

The beam control device may include the control unit 116. The beamconditioning device may include the beam irradiation regiondetermination unit 110. The beam conditioning device may include anenergy filter or a deflection element. The beam shaping device mayinclude a first XY convergence lens 206, a second XY convergence lens208, and a Y convergence lens 210, which are to be described below.

It can be considered that, in the case of the beam scanning method, theinitial ion beam B1 takes a single beam trajectory in the upstream partof the beamline device 104, and in the downstream part the implantationion beam B2 takes a plurality of beam trajectories due to the beamscanning and parallelizing with reference to the beam center trajectorybeing the reference. However, in the case of the ribbon beam, it becomesa beam irradiation zone because the beam cross-sectional shape of thesingle beam trajectory is changed and the beam width is widened. Thus,the beam trajectory is also single. According to this view, the beamirradiation region 105 may be also referred to as an ion beam trajectoryzone. Therefore, in the ion implantation apparatus 100, the implantationion beam B2 has the same ion beam trajectory zone in the first beamlinesetting S1 and the second beamline setting S2.

FIG. 4 is a flowchart illustrating an ion implantation method accordingto an embodiment of the present invention. This ion implantation methodis suitable for use in the ion implantation apparatus 100. This methodis performed by the control unit 116. As illustrated in FIG. 4, thismethod includes a beamline setting selecting step (S10) and an ionimplantation step (S20).

The control unit 116 selects a beamline setting suitable forgiven ionimplantation conditions among a plurality of beamline settings (S10). Asdescribed above, the plurality of beamline settings includes a firstbeamline setting S1 suitable for transport of a high-current beam forhigh-dose implantation into a workpiece, and a second beamline settingS2 suitable for transport of a low-current beam for low-doseimplantation into a workpiece. For example, the control unit 116 selectsthe first beamline setting S1 when a desired ion dose amount implantedinto a substrate W exceeds a threshold value, and selects the secondbeamline setting S2 when the desired ion dose amount is smaller than thethreshold value. Also, as described below, the plurality of beamlinesettings (or implantation setting configurations) may include a thirdbeamline setting (or third implantation setting configuration) and/or afourth beamline setting (or fourth implantation setting configuration).

When the first beamline setting S1 is selected, the control unit 116sets the energy adjustment system 112 by using the first energy setting.The energy adjustment system 112 and the power supply thereof areconnected according to a first power supply connection setting. Also,the control unit 116 sets the beam current adjustment system. 114 byusing the first beam current setting. Therefore, the ion beam passageregion (or adjustment range thereof) is set according to the firstopening setting. Likewise, when the second beamline setting S2 isselected, the control unit 116 sets the energy adjustment system 112 byusing the second energy setting, and sets the beam current adjustmentsystem 114 by using the second beam current setting.

The selecting process step may include a process step of adjusting thebeamline device 104 in the adjustment range according to the selectedbeamline setting. In the adjusting process step, each adjustment elementof the beamline device 104 is adjusted within a corresponding adjustmentrange so as to generate the ion beam of a desired implantationcondition. For example, the control unit 116 determines a voltage of apower supply corresponding to each adjustment element of the energyadjustment system 112 so as to obtain a desired implantation energy.Also, the control unit 116 determines the ion beam passage region of thebeam current adjustment element 124 so as to obtain a desiredimplantation dose amount.

In this manner, the control unit 116 operates the ion implantationapparatus 100 under the selected beamline setting (S20). Theimplantation ion beam B2 having the beam irradiation region 105 isgenerated and supplied to the substrate W. The implantation ion beam B2scans the entire substrate W in cooperation with the mechanical scanningof the substrate W (or with the beam alone). As a result, ions areimplanted into the substrate W at the energy and dose amount of thedesired ion implantation conditions.

The serial-type high-dose high-current ion implantation apparatus, whichis being used in device production, currently adopts a hybrid scanningmethod, a two-dimensional mechanical scanning method, and a ribbonbeam+wafer scanning method. However, the two-dimensional mechanicalscanning method has a limitation in increase of a scanning speed due toa load of mechanical driving mechanism of the mechanical scanning, andthus, the two-dimensional mechanical scanning method disadvantageouslycannot suppress implantation non-uniformity sufficiently. Also, in theribbon beam+wafer scanning method, uniformity is easily degraded whenthe beam size is expanded in a horizontal direction. Therefore, inparticular, there are problems in the uniformity and the identity ofbeam angle in the low-dose condition (low beam current condition).However, when the obtained implantation result is within an allowablerange, the ion implantation apparatus of the present invention may beconfigured by the two-dimensional mechanical scanning method or theribbon beam+wafer scanning method.

On the other hand, the hybrid scanning method can achieve excellentuniformity in the beam scanning direction by adjusting the bean scanningspeed at high accuracy. Also, by performing the beam scanning at asufficient high speed, implantation non-uniformity in the wafer scanningdirection can be sufficiently suppressed. Therefore, the hybrid scanningmethod is considered as optimal over a broad range of the dosecondition.

FIG. 5A is a plan view illustrating a schematic configuration of an ionimplantation apparatus 200 according to an embodiment of the presentinvention, and FIG. 5B is a side view illustrating a schematicconfiguration of an ion implantation apparatus 200 according to anembodiment of the present invention. The ion implantation apparatus 200is an embodiment when the hybrid scanning method is applied to the ionimplantation apparatus 100 illustrated in FIG. 2. Also, like the ionimplantation apparatus 100 illustrated in FIG. 2, the ion implantationapparatus 200 is a serial-type apparatus.

As illustrated, the ion implantation apparatus 200 includes a pluralityof beamline components. The beamline upstream part of the ionimplantation apparatus 200 includes, in order from the upstream side, anion source 201, a mass analysis magnet 202, a beam dump 203, a resolvingaperture 204, a current suppression mechanism 205, a first XYconvergence lens 206, a beam current measurement device 207, and asecond XY convergence lens 208. An extraction electrode 218 (see FIGS. 6and 7) for extracting ions from the ion source 201 is provided betweenthe ion source 201 and the mass analysis magnet 202.

A scanner 209 is provided between the beamline upstream part and thebeamline downstream part. The beamline downstream part includes, inorder from the upstream side, a Y convergence lens 210, a beamparallelizing mechanism 211, an AD (Accel/Decel) column 212, and anenergy filter 213. A wafer 214 is disposed in the most downstream partof the beamline downstream part. The beamline components from the ionsource 201 to the beam parallelizing mechanism 211 are accommodated in aterminal 216.

The current suppression mechanism 205 is an example of theabove-described beam current adjustment system 114. The currentsuppression mechanism 205 is provided for switching a low-dose mode anda high-dose mode. The current suppression mechanism 205 includes, forexample, a continuously variable aperture (CVA). The CVA is an aperturecapable of adjusting an opening size by a driving mechanism. Therefore,the current suppression mechanism 205 is configured to operate in arelatively small opening size adjustment range in the low-dose mode, andoperate in a relatively large opening size adjustment range in thehigh-dose mode. In an embodiment, in addition or alternative to thecurrent suppression mechanism 205, a plurality of resolving apertures204 having different opening widths may be configured to operate withdifferent settings in the low-dose mode and the high-dose mode.

The current suppression mechanism 205 serves to help beam adjustmentunder the low beam current condition by limiting an ion beam amountarriving at the downstream. The current suppression mechanism 205 isprovided in the beamline upstream part (that is, from the ion extractionfrom the ion source 201 to the upstream side of the scanner 209).Therefore, the beam current adjustment range can be increased. Also, thecurrent suppression mechanism 205 may be provided in the beamlinedownstream part.

The beam current measurement device 207 is, for example, a movable flagFaraday.

The first XY convergence lens 206, the second XY convergence lens 208,and the Y convergence lens 210 constitute the beam shaping device foradjusting the beam shape in the vertical and horizontal directions (beamcross-section in an XY plane). As such, the beam shaping device includesa plurality of lenses arranged along the beamline between the massanalysis magnet 202 and the beam parallelizing mechanism 211. The beamshaping device can use the convergence/divergence effect of these lensesin order to appropriately transport the ion beam up to the downstream ina broad range of energy/beam current condition. That is, the ion beamcan be appropriately transported to the wafer 214 in any condition oflow energy/low beam current, low energy/high beam current, highenergy/low beam current, and high energy/high beam current.

The first XY convergence lens 206 is, for example, a Q lens. The secondXY convergence lens 208 is, for example, an XY-direction einzel lens.The Y convergence lens 210 is, for example, a Y-direction einzel lens orQ lens. Each of the first XY convergence lens 206, the second XYconvergence lens 208, and the Y convergence lens 210 may be a singlelens or a group of lenses. In this manner, the beam shaping device isdesigned to appropriately control the ion beam from the low energy/highbeam current condition having a beam self-divergence problem caused by alarge beam potential to the high energy/low beam current having a beamcross-sectional shape control problem caused by a small beam potential.

The energy filter 213 is, for example, an angular energy filter (AEF)having a deflection electrode or a deflection electromagnet, or both ofthe defection electrode and the deflection electromagnet.

The ions generated in the ion source 201 are accelerated with anextraction electric field (not illustrated). The accelerated ions aredeflected in the mass analysis magnet 202. In this manner, only ionshaving a predetermined energy and a mass-to-charge ratio pass throughthe resolving aperture 204. Subsequently, the ions are guided to thescanner 209 through the current suppression mechanism (CVA) 205, thefirst XY convergence lens 206, and the second XY convergence lens 208.

The scanner 209 reciprocally scans the ion beam in a horizontaldirection (which may be a vertical direction or an oblique direction) byapplying either (or both) of a periodic electric field and a periodicmagnetic field. Due to the scanner 209, the ion beam is adjusted suchthat the ion beam is uniformly implanted in a horizontal direction onthe wafer 214. The traveling direction of the ion beam 215 with whichthe scanner 209 scans can be parallelized by the beam parallelizingmechanism 211 using the application of either (or both) of the electricfield and the magnetic field. Thereafter, the ion beam 215 isaccelerated or decelerated to have a predetermined energy in the ADcolumn 212 by applying the electric field. The ion beam 215 exiting theAD column 212 reaches the final implantation energy (in the low-energymode, the energy may be adjusted to be higher than the implantationenergy, and the ion beam may be deflected while decelerating in theenergy filter). The energy filter 213 in the downstream of the AD column212 deflects the ion beam 215 to the wafer 214 by the application ofeither (or both) of the electric field and the magnetic field with thedeflection electrode or the deflection electromagnet. Thus, acontamination with energy other than target energy is eliminated. Inthis manner, the purified ion beam 215 is implanted into the wafer 214.

Also, the beam dump 203 is disposed between the mass analysis magnet 202and the resolving aperture 204. The beam dump 203 deflects the ion beamby applying the electric field when necessary. Therefore, the beam dump203 can control the arrival of the ion beam at the downstream at highspeed.

Next, the low-energy mode and the high-energy mode in the ionimplantation apparatus 200 illustrated in FIG. 5 will be described withreference to the configuration system diagram of the high-voltage powersupply system 230 illustrated in FIGS. 6 and 7. FIG. 6 illustrates apower supply switching state of the low-energy mode, and FIG. 7illustrates a power supply switching state of the high-energy mode.FIGS. 6 and 7 illustrate main components related to the energyadjustment of the ion beam among the beamline components illustrated inFIG. 5. In FIGS. 6 and 7, the ion beam 215 is indicated by an arrow.

As illustrated in FIGS. 6 and 7, the beam parallelizing mechanism 211(see FIG. 5) includes a double P lens 220. The double P lens 220includes a first voltage gap 221 and a second voltage gap 222 disposedspaced apart from each other along the ion movement direction. The firstvoltage gap 221 is disposed in the upstream, and the second voltage gap222 is disposed in the downstream.

The first voltage gap 221 is formed between a pair of electrodes 223 and224. The second voltage gap 222 is formed between another pair ofelectrodes 225 and 226 disposed in the downstream of the electrodes 223and 224. The first voltage gap 221 and the electrodes 223 and 224forming the gap 221 have a convex shape toward the upstream side.Conversely, the second voltage gap 222 and the electrodes 225 and 226forming the gap 222 have a convex shape toward the downstream side.Also, for convenience of description, these electrodes may be alsoreferred to as a first P lens upstream electrode 223, a first P lensdownstream electrode 224, a second P lens upstream electrode 225, and asecond P lens downstream electrode 226 below.

The double P lens 220 parallelizes the incident ion beam before emissionand adjusts the energy of the ion beam by a combination of the electricfields applied to the first voltage gap 221 and the second voltage gap222. That is, the double P lens 220 accelerates or decelerates the ionbeam by the electric fields of the first voltage gap 221 and the secondvoltage gap 222.

Also, the ion implantation apparatus 200 includes a high-voltage powersupply system 230 including a power supply for the beamline components.The high-voltage power supply system 230 includes a first power supplyunit 231, a second power supply unit 232, a third power supply unit 233,a fourth power supply unit 234, and a fifth power supply unit 235. Asillustrated, the high-voltage power supply system 230 includes aconnection circuit for connecting the first to fifth power supply units231 to 235 to the ion implantation apparatus 200.

The first power supply unit 231 includes a first power supply 241 and afirst switch 251. The first power supply 241 is provided between the ionsource 201 and the first switch 251, and is a DC power supply thatprovides the ion source 201 with a positive voltage. The first switch251 connects the first power supply 241 to a ground 217 in thelow-energy mode (see FIG. 6), and connects the first power supply 241 toa terminal 216 in the high-energy mode (see FIG. 7). Therefore, thefirst power supply 241 provides a voltage V_(HV) to the ion source 201in the low-energy mode on the basis of a ground potential. This providesthe total ion energy as it is. On the other hand, the first power supply241 provides a voltage V_(HV) to the ion source 201 in the high-energymode on the basis of a terminal potential.

The second power supply unit 232 includes a second power supply 242 anda second switch 252. The second power supply 242 is provided between theterminal 216 and the ground 217, and is a DC power supply that providesthe terminal 216 with one of positive and negative voltages by theswitching of the second switch 252. The second switch 252 connects anegative electrode of the second power supply 242 to the terminal 216 inthe low-energy mode (see FIG. 6), and connects a positive electrode ofthe second power supply 242 to the terminal 216 in the high-energy mode(see FIG. 7). Therefore, the second power supply 242 provides a voltageV_(T) (V_(T)<0) to the terminal 216 in the low-energy mode on the basisof the ground potential. On the other hand, the second power supply 242provides a voltage V_(T) (V_(T)>0) to the terminal 216 in thehigh-energy mode on the basis of the ground potential.

Therefore, an extraction voltage V_(EXT) of the extraction electrode 218is V_(EXT)=V_(HV)−V_(T) in the low-energy mode, and is V_(EXT)=V_(HV) inthe high-energy mode. When a charge of an ion is q, the final energy isqV_(HV) in the low-energy mode, and is q(V_(HV)+V_(T)) in thehigh-energy mode.

The third power supply unit 233 includes a third power supply 243 and athird switch 253. The third power supply 243 is provided between theterminal 216 and the double P lens 220. The third power supply 243includes a first P lens power supply 243-1 and a second P lens powersupply 243-2. The first P lens power supply 243-1 is a DC power supplythat provides a voltage V_(AP) to the first P lens downstream electrode224 and the second P lens upstream electrode 225 on the basis of theterminal potential. The second P lens power supply 243-2 is a DC powersupply that provides a voltage V_(DP) to a destination through the thirdswitch 253 on the basis of the terminal potential. The third switch 253is provided between the terminal 216 and the double P lens 220 toconnect one of the first P lens power supply 243-1 and the second P lenspower supply 243-2 to the second P lens downstream electrode 226 by theswitching. Also, the first P lens upstream electrode 223 is connected tothe terminal 216.

The third switch 253 connects the second P lens power supply 243-2 tothe second P lens downstream electrode 226 in the low-energy mode (seeFIG. 6), and connects the first P lens power supply 243-1 to the secondP lens downstream electrode 226 in the high-energy mode (see FIG. 7).Therefore, the third power supply 243 provides a voltage V_(DP) to thesecond P lens downstream electrode 226 in the low-energy mode on thebasis of the terminal potential. On the other hand, the third powersupply 243 provides a voltage V_(AP) to the second P lens downstreamelectrode 226 in the high-energy mode on the basis of the terminalpotential.

The fourth power supply unit 234 includes a fourth power supply 244 anda fourth switch 254. The fourth power supply 244 is provided between thefourth switch 254 and the ground 217 and is a DC power supply thatprovides a negative voltage to an exit (that is, the downstream end) ofthe AD column 212. The fourth switch 254 connects the fourth powersupply 244 to the exit of the AD column 212 in the low-energy mode (seeFIG. 6), and connects the exit of the AD column 212 to the ground 217 inthe high-energy mode (see FIG. 7). Therefore, the fourth power supply244 provides a voltage V_(ad) to the exit of the AD column 212 in thelow-energy mode on the basis of the ground potential. On the other hand,the fourth power supply 244 is not used in the high-energy mode.

The fifth power supply unit 235 includes a fifth power supply 245 and afifth switch 255. The fifth power supply 245 is provided between thefifth switch 255 and the ground 217. The fifth power supply 245 isprovided for the energy filter (AEF) 213. The fifth switch 255 isprovided for switching the operation modes of the energy filter 213. Theenergy filter 213 is operated in a so-called offset mode in thelow-energy mode, and is operated in a normal mode in the high-energymode. The offset mode is an operation mode of the AEF in which anaverage value of the positive electrode and the negative electrode is anegative potential. The beam convergence effect of the offset mode canprevent beam loss caused by the beam divergence in the AEF. The normalmode is an operation mode of the AEF in which an average value of thepositive electrode and the negative electrode is the ground potential.

The ground potential is provided to the wafer 214.

FIG. 8A illustrates an example of a voltage applied to each portion ofthe ion implantation apparatus 200 in the low-energy mode, and FIG. 8Billustrates an example of energy of the ion in each portion of the ionimplantation apparatus 200 in the low-energy mode. FIG. 9A illustratesan example of a voltage applied to each portion of the ion implantationapparatus 200 in the high-energy mode, and FIG. 9B illustrates anexample of energy of the ion in each portion of the ion implantationapparatus 200 in the high-energy mode. The vertical axes in FIGS. 8A and9A represent the voltage, and the vertical axes in FIGS. 8B and 9Brepresent the energy. In the horizontal axes of the respective drawings,locations in the ion implantation apparatus 200 are represented bysymbols a to g. The symbols a, b, c, d, e, f, and P represent the ionsource 201, the terminal 216, the acceleration P lens (first P lensdownstream electrode 224), the deceleration P lens (second P lensdownstream electrode 226), the exit of the AD column 212, the energyfilter 213, and the wafer 214, respectively.

The double P lens 220 has a configuration that uses the acceleration Plens c alone, or uses the deceleration P lens d alone, or uses both ofthe acceleration P lens c and the deceleration P lens d, when necessaryaccording to the implantation condition. In the configuration that usesboth of the acceleration P lens c and the deceleration P lens d, thedouble P lens 220 can be configured to change the distribution of theacceleration and deceleration effects by using both of the accelerationeffect and the deceleration effect. In this case, the double P lens 220can be configured such that a difference between the incident beamenergy to the double P lens 220 and the exit beam energy from the doubleP lens 220 is used to accelerate or decelerate the beam. Alternatively,the double P lens 220 can be configured such that the difference betweenthe incident beam energy and the exit beam energy becomes zero, andthus, the beam is neither accelerated nor decelerated.

As an example, as illustrated, in the low-energy mode, the double P lens220 is configured to decelerate the ion beam in the deceleration P lensd, accelerate the ion beam in the acceleration P lens c to some extentwhen necessary, and thereby the ion beam is decelerated as a whole. Onthe other hand, in the high-energy mode, the double P lens 220 isconfigured to accelerate the ion beam only in the acceleration P lens c.Also, in the high-energy mode, the double P lens 220 may be configuredto decelerate the ion beam in the deceleration P lens d to some extentwhen necessary, as long as the ion beam is accelerated as a whole.

Since the high-voltage power supply system 230 is configured as above,the voltages applied to several regions on the beamline can be changedby the switching of the power supply. Also, the voltage applicationpaths in some regions can also be changed. By using these, it ispossible to switch the low-energy mode and the high-energy mode in thesame beamline.

In the low-energy mode, the potential V_(HV) of the ion source 201 isdirectly applied on the basis of the ground potential. Therefore, ahigh-accuracy voltage application to the source unit is possible, andthe accuracy of energy setting can be increased during the ionimplantation at low energy. Also, by setting the terminal voltage V_(T),the P lens voltage V_(DP), the AD column exit voltage V_(ad), and theenergy filter voltage V_(bias) to negative, it is possible to transportthe ions to the energy filter at a relatively high energy. Therefore,the transport efficiency of the ion beam can be improved, and the highcurrent can be obtained.

Also, in the low-energy mode, the deceleration P lens is employed tofacilitate the ion beam transport in the high-energy state. This helpsthe low-energy mode coexist with the high-energy mode in the samebeamline. Also, in the low-energy mode, an expanded beam by design isgenerated by adjusting the convergence/divergence elements of thebeamline in order to transport the beam such that the self-divergence ofthe beam is minimized. This also helps the low-energy mode coexist withthe high-energy mode in the same beamline.

In the high-energy mode, the potential of the ion source 201 is the sumof the acceleration extraction voltage V_(HV) and the terminal potentialV_(T). This can enable the application of the high voltage to the sourceunit, and accelerate ions at high energy.

FIG. 10 is a flowchart illustrating an ion implantation method accordingto an embodiment of the present invention. This method may be performedby, for example, the beam control device for the ion implantationapparatus. As illustrated in FIG. 10, first, the implantation recipe isselected (S100). The control device reads the recipe condition (S102),and selects the beamline setting according to the recipe condition(S104). The ion beam adjusting process is performed under the selectedbeamline setting. The adjusting process includes a beam emission andadjustment (S106) and an obtained beam checking (S108). In this manner,the preparing process for the ion implantation is ended. Next, the waferis loaded (S110), the ion implantation is performed (S112), and thewafer is unloaded (S114). Steps 110 to 114 may be repeated until thedesired number of wafers are processed.

FIG. 11 schematically illustrates a range D of energy and dose amountthat is realized by the ion implantation apparatus 200. Like in FIG. 1,FIG. 11 illustrates the range of energy and dose amount that can beprocessed in the actually allowable productivity. For comparison, rangesA, B and C of energy and dose amount of the HC, the MC, and the HEillustrated in FIG. 1 are illustrated in FIG. 11.

As illustrated in FIG. 11, it can be seen that the ion implantationapparatus 200 includes all the operation ranges of the existingapparatuses HC and MC. Therefore, the ion implantation apparatus 200 isa novel apparatus beyond the existing framework. Even one novel ionimplantation apparatus can serve as the two existing types of categoriesHC and MC while maintaining the same beamline and the implantationmethod. Therefore, this apparatus may be referred to as HCMC.

Therefore, according to the present embodiment, it is possible toprovide the HCMC in which the serial-type high-dose high-current ionimplantation apparatus and the serial-type medium-dose medium-currention implantation apparatus are configured as a single apparatus. TheHCMC can perform the implantation in a broad range of energy conditionand dose condition by changing the voltage applying method in thelow-energy condition and the high-energy condition and changing the beamcurrent from high current to low current in the CVA.

Also, the HCMC-type ion implantation apparatus may not include all theimplantation condition ranges of the existing HC and MC. Considering thetradeoff of the device manufacturing cost and the implantationperformance, it may be thought to provide an apparatus having a range E(see FIG. 12) narrower than the range D illustrated in FIG. 11. In thiscase, the ion implantation apparatus having excellent practicality canbe provided as long as it covers the ion implantation conditionsrequired for the device maker.

The improvement in the operation efficiency of the apparatus realized bythe HCMC in the device manufacturing process will be described. Forexample, as illustrated in FIG. 13, it is assumed that a device makeruses six HCs and four MCs in order to process a manufacturing process X(that is, this device maker owns only the existing apparatuses HC andMC). Thereafter, the device maker changes the process X to a process Yaccording to a change in a manufacturing device. As a result, the devicemaker needs eight HCs and two MCs. The maker needs to install two moreHCs, and thus, the increase in investment and the lead time arerequired. At the same time, two MCs are not operated, and thus, themaker unnecessarily owns these. As described above, since the HC and theMC are generally different in the implantation method, it is difficultto convert the non-operating MCs to newly necessary HCs.

Next, as illustrated in FIG. 14, it is considered that the device makeruses six HCs, two MCs, and two HCMCs in order to process the process X.In this case, even when the process X is changed to the process Yaccording to the change in the manufacturing device, the HCMC can beoperated as the HC because the HCMC is the process shared machine of theHC and the MC. Therefore, additional equipment installation andnon-operation are unnecessary.

As such, there is a great merit when the device maker owns a certainnumber of HCMCs. This is because the process change of HC and the MC canbe absorbed by the HCMC. Also, when some apparatuses cannot be used dueto malfunction or maintenance, the HCMC can also be used as the HC orthe MC. Therefore, by owning the HCMC, the overall operating rate of theapparatus can be significantly improved.

Also, ultimately, it can be considered that all apparatuses are providedwith HCMCs. However, in many cases, it is practical that part of theapparatuses are provided with HCMCs considering a price differencebetween the HCMC and the HC (or MC) or the utilization of the alreadyowned HC or MC.

Also, when a type of the existing ion implantation apparatus is replacedwith other apparatuses having different methods of implanting ions intothe wafer in order for an ion implantation process to be performed, itmay be difficult to match the implantation characteristics. This isbecause a beam divergence angle or a beam density may be different eventhough the energy and dose are matched in two types of ion implantationapparatuses for the ion implantation process. However, the HCMC canprocess the high-dose high-current ion implantation condition and themedium-dose medium-current ion implantation condition on the samebeamline (the same ion beam trajectory). In this way the HCMC canseparately use the high-dose high-current ion implantation condition andthe medium-dose medium-current ion implantation condition. Therefore, itis expected to facilitate the matching because the change in theimplantation characteristics followed by the replacement of theapparatus is sufficiently suppressed.

The HCMC is the shared machine of the HC and the MC and can also processthe implantation condition out of the operation range of the existing HCor the MC. As illustrated in FIG. 11, the HCMC is a new apparatus thatcan also process the high energy/high dose implantation (right upperregion F in the range D) and low energy/low dose implantation (leftlower region G in the range D). Therefore, in addition or alternative tothe first beamline setting S1 and the second beamline setting S2described above, in an embodiment, the ion implantation apparatus mayinclude a third beamline setting for high energy/high dose implantationand/or a fourth beamline setting for low energy/low dose implantation.

As described above, in the present embodiment, the beamlines of theserial-type high-dose high-current ion implantation apparatus and theserial-type medium-dose medium-current ion implantation apparatus arematched and shared. Moreover, a structure for switching the beamlineconfiguration is constructed. In this manner, the implantationprocessing is possible over a broad range of energy and beam currentregions on the same beamline (the same ion beam trajectory and the sameimplantation method).

The present invention has been described based on the embodiments. Thepresent invention is not limited to the embodiments, and it can beunderstood by those skilled in the art that designs can be modified invarious ways, various modifications can be made, and such modificationsfall within the scope of the present invention.

In addition or alternative to the above-described configurations, thequantitative adjustment of the beam current by the beam currentadjustment system can be configured in various ways. For example, whenthe beam current adjustment system includes a variable-width aperturearranged on the beamline, the variable-width aperture may be disposed atany arbitrary position. Therefore, the variable-width aperture may bedisposed between the ion source and the mass analysis magnet, betweenthe mass analysis magnet and the mass analysis slit, between the massanalysis slit and the beam shaping device, between the beam shapingdevice and the beam control device, between the beam control device andthe beam conditioning device, between the respective elements of thebeam conditioning device, and/or between the beam conditioning deviceand the workpiece. The variable-width aperture may be the mass analysisslit.

The beam current adjustment may be configured to adjust the amount ofion beam passing through the aperture by arranging thedivergence/convergence lens system before and/or after a fixed-widthaperture. The fixed-width aperture may be the mass analysis slit.

The beam current adjustment may be performed using an energy slitopening width variable (and/or a beamline end opening width variableslit apparatus). The beam current adjustment may be performed using ananalyzer magnet (mass analysis magnet) and/or a steerer magnet(trajectory modification magnet). The dose amount adjustment may beaccompanied by an expansion of the variable range of mechanical scanspeed (for example, from ultra-low speed to ultra-high speed) and/or achange in the number of times of the mechanical scanning.

The beam current adjustment may be performed by the adjustment of theion source (for example, amount of gas or arc current). The beam currentadjustment may be performed by the exchange of the ion source. In thiscase, the ions source for MC and the ion source for HC may beselectively used. The beam current adjustment may be performed by thegap adjustment of the extraction electrode of the ion source. The beamcurrent adjustment may be performed by providing the CVA immediatelydownstream of the ion source.

The beam current adjustment may be performed according to the change inthe vertical width of the ribbon beam. The dose amount adjustment may beperformed according to the change in the scanning speed during thetwo-dimensional mechanical scanning.

The beamline device may include a plurality of beamline componentsconfigured to operate under only one of the first beamline setting andthe second beamline setting, and thus, the ion implantation apparatusmay be configured as a high-current ion implantation apparatus or amedium-current ion implantation apparatus. That is, with the HCMC as aplatform, for example, by exchanging some beamline components, orchanging the power supply configuration, the serial-type high-dosededicated ion implantation apparatus or the serial-type medium-dosededicated ion implantation apparatus can be produced from theserial-type high-dose medium-dose wide-use ion implantation apparatus.Since it is expected to manufacture each dedicated apparatus at lowercost than the wide-use apparatus, it can contribute to reducing themanufacturing costs for the device maker.

In the MC, implantation at higher energy may be achieved by usingmultivalent ions such as divalent ions or trivalent ions. However, inthe typical ion source (thermionic emission type ion source), thegeneration efficiency of multivalent ions is much lower than thegeneration efficiency of monovalent ions. Therefore, practical doseimplantation in the high-energy range is actually difficult. When amultivalent ion enhancement source, such as an RF ion source, isemployed as the ion source, tetravalent or pentavalent ions can beobtained. Therefore, more ion beams can be obtained in the higher energycondition.

Therefore, by employing the multivalent ion enhancement source, such asthe RF ion source, as the ion source, the HCMC can operate as theserial-type high energy ion implantation apparatus (HE). Therefore, aportion of the implantation condition that has been processed by onlythe serial-type high energy/low-dose ion implantation apparatus can beprocessed by the HCMC (the range of the MC illustrated in FIG. 8 may beexpanded to include at least a portion of the range C).

Hereinafter, several aspects of the present invention will be described.

An ion implantation apparatus according to an embodiment includes: anion source for generating ions and extracting the ions as an ion beam;an implantation processing chamber for implanting the ions into aworkpiece; and a beamline device for providing a beamline to transportthe ion beam from the ion source to the implantation processing chamber,wherein the beamline device supplies the ion beam having a beamirradiation region exceeding the width of the workpiece in theimplantation processing chamber, the implantation processing chamberincludes a mechanical scanning device for mechanically scanning theworkpiece with respect to the beam irradiation region, the beamlinedevice is operated under one of a plurality of implantation settingconfigurations according to an implantation condition, the plurality ofimplantation setting configurations including a first implantationsetting configuration suitable for transport of a low energy/highcurrent beam for high-dose implantation into the workpiece, and a secondimplantation setting configuration suitable for transport of a highenergy/low current beam for low-dose implantation into the workpiece,and the beamline device is configured such that a same beam centertrajectory being a reference in the beamline is provided from the ionsource to the implantation processing chamber in the first implantationsetting configuration and the second implantation setting configuration.

An ion implantation apparatus according to an embodiment includes: anion source for generating ions and extracting the ions as an ion beam;an implantation processing chamber for implanting the ions into aworkpiece; and a beamline device for providing a beamline to transportthe ion beam from the ion source to the implantation processing chamber,wherein the ion implantation apparatus is configured to irradiate theworkpiece with the ion beam in cooperation with mechanical scanning ofthe workpiece, the beamline device is operated under one of a pluralityof implantation setting configurations according to an implantationcondition, the plurality of implantation setting configurationsincluding a first implantation setting configuration suitable fortransport of a low energy/high current beam for high-dose implantationinto the workpiece, and a second implantation setting configurationsuitable for transport of a high energy/low current beam for low-doseimplantation into the workpiece, and the beamline device is configuredsuch that a same beam center trajectory being a reference in thebeamline is provided from the ion source to the implantation processingchamber in the first implantation setting configuration and the secondimplantation setting configuration.

The beamline device may take the same implantation method in the firstimplantation setting configuration and the second implantation settingconfiguration. The beam irradiation region may be equal in the firstimplantation setting configuration and the second implantation settingconfiguration.

The beamline apparatus may include a beam conditioning device forconditioning the ion beam, and a beam shaping device for shaping the ionbeam. The beam conditioning device and the beam shaping device in thebeamline device may be disposed in the same layout in the firstimplantation setting configuration and the second implantation settingconfiguration. The beam implantation apparatus may have the sameinstallation floor area in the first implantation setting configurationand the second implantation setting configuration.

The beamline device may include a beam current adjustment system foradjusting the total amount of beam current of the ion beam. The firstimplantation setting configuration may include a first beam currentsetting for the beam current adjustment system, the second implantationsetting configuration may include a second beam current setting for thebeam current adjustment system, and the second beam current setting maybe determined to make the beam current of the ion beam smaller than thatof the first beam current setting.

The beam current adjustment system may be configured to block at least aportion of the ion beam when passing through an adjustment element. Thebeam current adjustment system may include a variable-width aperturearranged on the beamline. The beam current adjustment system may includea beamline end opening width variable slit device. The ion source may beconfigured to adjust the total amount of beam current of the ion beam.The ion source may include an extraction electrode for extracting theion beam, and the total amount of beam current of the ion beam may beadjusted by adjusting an opening of the extraction electrode.

The beamline device may include an energy adjustment system foradjusting an implantation energy of the ions into the workpiece. Thefirst implantation setting configuration may include a first energysetting for the energy adjustment system, the second implantationsetting configuration may include a second energy setting for the energyadjustment system, the first energy setting may be suitable fortransport of a lower energy beam as compared with the second energysetting.

The energy adjustment system may include a beam parallelizing device forparallelizing the ion beam. The beam parallelizing device may beconfigured to decelerate, or decelerate and accelerate the ion beamunder the first implantation setting configuration, and accelerate, oraccelerate and decelerate the ion beam under the second implantationsetting configuration. The beam parallelizing device may include anacceleration lens for accelerating the ion beam, and a deceleration lensfor decelerating the ion beam, and may be configured to modify adistribution of acceleration and deceleration, and the beamparallelizing device may be configured to mainly decelerate the ion beamunder the first implantation setting configuration, and mainlyaccelerate the ion beam under the second implantation settingconfiguration.

The beamline device may include a beam current adjustment system foradjusting the total amount of beam current of the ion beam, and anenergy adjustment system for adjusting an implantation energy of theions into the workpiece, and may adjust the total amount of the beamcurrent and the implantation energy individually or simultaneously. Thebeam current adjustment system and the energy adjustment system may beseparate beamline components.

The ion implantation apparatus may include a control unit configured tomanually or automatically select one implantation setting configurationsuitable for a given ion implantation condition among the plurality ofimplantation setting configurations including the first implantationsetting configuration and the second implantation setting configuration.

The control unit may select the first implantation setting configurationwhen a desired ion dose amount implanted into the workpiece is in therange of about 1×10¹⁴ to 1×10¹⁷ atoms/cm², and may select the secondimplantation setting configuration when a desired ion dose amountimplanted into the workpiece is in the range of about 1×10¹¹ to 1×10¹⁴atoms/cm².

The beamline device may have a first energy adjustment range under thefirst implantation setting configuration, and may have a second energyadjustment range under the second implantation setting configuration,and the first energy adjustment range and the second energy adjustmentrange may have a partially overlapped range.

The beamline device may have a first dose adjustment range under thefirst implantation setting configuration, and may have a second doseadjustment range under the second implantation setting configuration,and the first dose adjustment range and the second dose adjustment rangemay have a partially overlapped range.

The beamline device may include a beam scanning device for providingscanning of the ion beam to form an elongated irradiation regionextending in a longitudinal direction perpendicular to a beam transportdirection. The implantation processing chamber may include a workpieceholder configured to provide mechanical scanning of the workpiece in adirection perpendicular to the longitudinal direction and the beamtransport direction.

The beamline device may include a ribbon beam generator for generating aribbon beam having an elongated irradiation region extending in alongitudinal direction perpendicular to a beam transport direction. Theimplantation processing chamber may include a workpiece holderconfigured to provide mechanical scanning of the workpiece in adirection perpendicular to the longitudinal direction and the beamtransport direction.

The implantation processing chamber may include a workpiece holderconfigured to provide mechanical scanning of the workpiece in twodirections perpendicular to each other in a plane perpendicular to thebeam transport direction.

The beamline device may be configured to be selectable from a pluralityof beamline components configured to be operated under only one of thefirst implantation setting configuration and the second implantationsetting configuration, and the ion implantation apparatus may beconfigured as a high-current dedicated ion implantation apparatus or amedium-current dedicated ion implantation apparatus.

An ion implantation method according to an embodiment includes:selecting one implantation setting configuration, with respect to abeamline device, which is suitable for a given ion implantationcondition among a plurality of implantation setting configurationsincluding a first implantation setting configuration suitable fortransport of a low energy/high current beam for high-dose implantationinto a workpiece, and a second implantation setting configurationsuitable for transport of a high energy/low current beam for low-doseimplantation into the workpiece; transporting an ion beam along a beamcenter trajectory being a reference in a beamline from an ion source toan implantation processing chamber by using the beamline device underthe selected implantation setting configuration; and irradiating theworkpiece with the ion beam in cooperation with mechanical scanning ofthe workpiece, wherein the beam center trajectory being the reference isequal in the first implantation setting configuration and the secondimplantation setting configuration.

The transporting may include adjusting an implantation dose amount intothe workpiece by adjusting the total amount of beam current of the ionbeam. The implantation dose amount may be adjusted in a first doseadjustment range under the first implantation setting configuration, andmay be adjusted in a second dose adjustment range under the secondimplantation setting configuration, the second dose adjustment rangeincluding a dose range smaller than the first dose adjustment range.

The transporting may include adjusting the implantation energy into theworkpiece. The implantation energy may be adjusted in a first energyadjustment range under the first implantation setting configuration, andmay be adjusted in a second energy adjustment range under the secondimplantation setting configuration, the second energy adjustment rangeincluding an energy range higher than the first energy adjustment range.

1. An ion implantation apparatus according to an embodiment has the samebeam trajectory and the same implantation method and has a broad energyrange by switching a connection of a power supply for deceleration as awhole and a connection of a power supply for acceleration as a whole.

2. An ion implantation apparatus according to an embodiment has the samebeam trajectory and the same implantation method and has a broad beamcurrent range by including a device for cutting a portion of beam in abeamline upstream part in a beamline capable of obtaining a highcurrent.

3. An ion implantation apparatus according to an embodiment may have thesame beam trajectory and the same implantation method and have a broadenergy range and a broad beam current range by including both of thefeatures of the embodiment 1 and the embodiment 2.

An ion implantation apparatus according to an embodiment may be anapparatus that combines a beam scanning and a mechanical wafer scanningas the same implantation method in the embodiments 1 to 3. An ionimplantation apparatus according to an embodiment may be an apparatusthat combines a ribbon-shaped beam and a mechanical wafer scanning asthe same implantation method in the embodiments 1 to 3. An ionimplantation apparatus according to an embodiment may be an apparatusthat combines a two-dimensional mechanical wafer scanning as the sameimplantation method in the embodiments 1 to 3.

4. An ion implantation apparatus according to an embodiment isconfigured to freely select/switch a high-dose high-current ionimplantation and a medium-dose medium-current ion implantation byconfiguring a high-dose high-current ion implantation beamline componentand a medium-dose medium-current ion implantation beamline component inparallel on the same beamline (the same ion beam trajectory and the sameimplantation method), and covers a very broad energy range from lowenergy to high energy and a very broad dose range from a low dose to ahigh dose.

5. In the embodiment 4, each beamline component shared in the high doseuse and the medium dose use and each beamline component individuallyswitched in the high dose/medium dose use may be configured on the samebeamline.

6. In the embodiment 4 or 5, in order to adjust the beam current amountin a broad range, a beam limiting device (vertical or horizontalvariable-width slit, or rectangular or circular variable opening) forphysically cutting a portion of beam in a beamline upstream part may beprovided.

7. In any one of the embodiments 4 to 6, a switch controller controldevice may be provided to select a high-dose high-current ionimplantation and a medium-dose medium-current ion implantation, based ona desired ion dose amount implanted into the workpiece.

8. In the embodiment 7, the switch controller is configured to operatethe beamline in a medium-dose acceleration (extraction)/acceleration (Plens)/acceleration or deceleration (AD column) mode when a desired iondose amount implanted into the workpiece is in the medium-dosemedium-current range of about 1×10¹¹ to 1×10¹⁴ atoms/cm², and operatethe beamline in a high-dose acceleration (extraction)/deceleration (Plens)/deceleration (AD column) mode when a desired ion dose amountimplanted into the workpiece is in the high-dose high-current range ofabout 1×10¹⁴ to 1×10¹⁷ atoms/cm².

9. In any one of the embodiments 4 to 8, an apparatus for implantingions of relatively high energy by using an acceleration mode and anapparatus for implanting ions of relatively low energy by using adeceleration mode may have a mutually overlapped energy range.

10. In any one of the embodiments 4 to 8, an apparatus for implantingions of relatively high energy by using an acceleration mode and anapparatus for implanting ions of relatively low energy by using adeceleration mode may have a mutually overlapped dose range.

11. In any one of the embodiments 4 to 6, by limiting the beamlinecomponents, the ion implantation apparatus may easily be changed to ahigh-dose high-current dedicated ion implantation apparatus or amedium-dose medium-current dedicated ion implantation apparatus.

12. In anyone of the embodiments 4 to 11, the beamline configuration maycombine a beam scanning and a mechanical substrate scanning.

13. In anyone of the embodiments 4 to 11, the beamline configuration maycombine a mechanical substrate scanning and a ribbon-shaped beam havinga width equal to or greater than a width of a substrate (or wafer orworkpiece).

14. In anyone of the embodiments 4 to 11, the beamline configuration mayinclude a mechanical substrate scanning in a two-dimensional direction.

FIG. 15 is a perspective cross-sectional view illustrating aconfiguration of a scanning unit 1000 included in an ion implantationapparatus according to an embodiment of the present invention. The ionimplantation apparatus includes the scanning unit 1000 that includes anupstream electrode device 300, a scanning electrode device 400, and adownstream electrode device 500. The upstream electrode device 300, thescanning electrode device 400, and the downstream electrode device 500which are illustrated in the present drawing have a vertically andhorizontally symmetric shape with respect to a reference trajectory ofan ion beam B which is incident into the scanning unit 1000. In thepresent drawing, a lower half configuration thereof is only illustratedin order to facilitate understanding.

The upstream electrode device 300 is disposed just upstream of thescanning electrode device 400, and shapes a profile of an ion beam whichis incident into the scanning electrode device 400. The upstreamelectrode device 300 is configured by a plurality of electrode bodies,and includes a first upstream reference voltage electrode 310, anupstream intermediate electrode 330, and a second upstream referencevoltage electrode 350. The upstream electrode device 300 can be used as,for example, the second XY focusing lens 208 of the ion implantationapparatus 200 illustrated in FIGS. 5A and 5B.

The scanning electrode device 400 allows a deflecting electric field toact on the ion beam incident into the scanning electrode device 400 andprovides periodical scanning of the ion beam in a horizontal direction(x direction). The scanning electrode device 400 includes a pair ofscanning electrodes 410R and 410L (hereinafter, also collectivelyreferred to as a scanning electrode 410) that allow a deflectingelectric field to act on the ion beam and a beam transport correctionelectrode 450. The beam transport correction electrode 450 is providedto suppress a so-called “zero field effect”, in which when thedeflecting electric field applied by the scanning electrodes 410R and410L becomes zero, the diameter of the ion beam is reduced as comparedto a case in which the deflected filed is applied. A pair of beamtransport correction electrodes 450 are provided, which face each otherin a vertical direction (y direction). In this drawing, there isillustrated only a lower correction electrode 450B disposed in the lowerside. The scanning electrode device 400 can be used as, for example, thescanner 209 of the ion implantation apparatus 200 illustrated in FIGS.5A and 5B.

The downstream electrode device 500 is disposed just downstream of thescanning electrode device 400, and shapes a profile of an ion beamscanned by the scanning electrode device 400. The downstream electrodedevice 500 is configured by a plurality of electrode bodies, andincludes a first downstream reference voltage electrode 510, a firstdownstream intermediate electrode 530, a second downstream referencevoltage electrode 550, a second downstream intermediate electrode 570,and a third downstream reference voltage electrode 590. The downstreamelectrode device 500 can be used as, for example, the Y focusing lens210 of the ion implantation apparatus 200 illustrated in FIGS. 5A and5B.

FIGS. 16A and 16B are cross-sectional views schematically illustrating aconfiguration of the scanning unit 1000 illustrated in FIG. 15. FIG. 16Aillustrates a horizontal direction cross-section (xz-planecross-section) including a reference trajectory Z when it is assumedthat the reference trajectory Z of an ion beam extends in a z direction.FIG. 16B illustrates a vertical direction cross-section (yz-planecross-section) including the reference trajectory Z. Hereinafter, thescanning electrode device 400, the upstream electrode device 300, andthe downstream electrode device 500 in the scanning unit 1000 will bedescribed in order with reference to the present drawings.

FIG. 17 is a diagram schematically illustrating the scanning electrodedevice 400, which illustrates X-X cross-section of FIG. 16A. The pair ofscanning electrodes 410R and 410L are provided to face each other in ahorizontal direction (x direction) with respect to the referencetrajectory Z of the ion beam. B. The scanning electrodes 410R and 410Lrespectively include electrode inner surfaces 412R and 412L each havinga substantially concave shape. By using an electrode having asubstantially concave shape, it is possible to deflect the ion beam Bhaving a horizontally-elongated cross-sectional shape uniformly at thesame angle. Also, the cross-sectional shape of the ion beam B asindicated by a dashed line schematically illustrates a shape in thevicinity of an inlet 402 of the scanning electrode device 400illustrated in FIGS. 16A and 16B.

As illustrated in FIG. 16A, the scanning electrodes 410R and 410L have afolding-fan shape such that a distance between the right electrode innersurface 412R and the left electrode inner surface 412L increases towarda downstream direction. Therefore, it is possible to deflect the ionbeam B, which is deflected to be close to one of the right scanningelectrode 410R and the left scanning electrode 410L, uniformly at thesame angle in the vicinity of an outlet 404 of the scanning electrodedevice 400.

The pair of beam transport correction electrodes 450A and 450B(hereinafter, also collectively referred to as a beam transportcorrection electrode 450) are provided to face each other in a verticaldirection (y direction) with respect to the reference trajectory Z ofthe ion beam B. The beam transport correction electrode 450 is formed ofa plate-shaped member having a thickness d in a horizontal direction (xdirection). It is preferable that the thickness d of the beam transportcorrection electrode 450 is thick enough to have a strength to standalone and is thin enough to limit an effect due to the beam transportcorrection electrode 450 to the vicinity of the reference trajectory Z.The reason for this is that the “zero field effect” which is intended tobe suppressed by the beam transport correction electrode 450 occurs whenthe deflecting electric field becomes zero, and the ion beam travelsalong the reference trajectory Z. A positive bias voltage of aboutseveral kV to 20 kV is applied to the beam transport correctionelectrode 450, for example, a voltage of about +10 kV is applied to thebeam transport correction electrode 450.

Each of the beam transport correction electrodes 450A and 450B includesa straight portion 452 extending from the inlet 402 of the scanningelectrode device 400 to the outlet 404, and a beam transport correctioninlet electrode body 454 protruding from the straight portion 452 towardthe reference trajectory Z in a vertical direction. The straight portion452 mainly has a function of suppressing occurrence of the zero fieldeffect with respect to the entire scanning electrode device 400. On theother hand, the beam transport correction inlet electrode body 454mainly has a function of allowing ion beams passing through the vicinityof the reference trajectory Z to vertically converge substantially atthe inlet 402 of the scanning electrode device 400.

The beam transport correction inlet electrode body 454 is provided inthe vicinity of the inlet 402 of the scanning electrode device 400. Asillustrated in FIG. 16B, the beam transport correction inlet electrodebody 454 is provided such that a length L_(b) in a z direction is equalto or smaller than one third of a total length L_(a) of the beamtransport correction electrode 450 including the straight portion 452.It is preferable that the length L_(b) of the beam transport correctioninlet electrode body 454 is in a range from about one fourth to aboutone fifth of the total length L_(a) of the beam transport correctionelectrode 450. Accordingly, it is possible to limit the effect of thevertical focusing by the beam transport correction inlet electrode body454 to the vicinity of the inlet 402 of the scanning electrode device400. Also, by thinning the thickness d of the beam transport correctioninlet electrode body 454, the effect of the vertical focusing is limitedto ions passing through the vicinity of the reference trajectory Z, andinfluence on the ions passing through the outer side than the referencetrajectory Z is suppressed.

As illustrated in FIG. 17, the beam transport correction inlet electrodebody 454 is provided such that an end 454 a is adjacent to the ion beamB. In this case, a distance h₀ between the reference trajectory Z andthe end 454 a needs to be adjusted to a distance enough to reduceinfluence on a deflecting electric field generated by the scanningelectrode 410 and, at the same time, to allow influence due to the beamtransport correction inlet electrode body 454 to act on the vicinity ofthe reference trajectory Z. It is preferable that the distance h₀between the reference trajectory Z and the end 454 a is about severaltimes a diameter D_(y) in a vertical direction of the ion beam B, forexample, the distance h₀ may be in a range from about three times toabout four times the diameter D_(y).

Returning to FIGS. 16A and 16B, the upstream electrode device 300 willbe described below.

Electrodes that constitute the upstream electrode device 300 arearranged in the order of the first upstream reference voltage electrode310, the upstream intermediate electrode 330, and the second upstreamreference voltage electrode 350 from the inlet 402 of the scanningelectrode device 400 toward an upstream direction.

The first upstream reference voltage electrode 310, the upstreamintermediate electrode 330, and the second upstream reference voltageelectrode 350 respectively include openings 312, 332, and 352 for ionbeam passage. The ion beam B incident into the upstream electrode device300 has a horizontally-elongated flat shape, and the openings 312, 332and 352 of the electrodes constituting the upstream electrode device 300have a horizontally-elongated rectangular cross-sectional shape. Forexample, the shape of the opening 312 of the first upstream referencevoltage electrode 310 is illustrated in FIG. 18A which will be describedbelow.

The first upstream reference voltage electrode 310 and the secondupstream reference voltage electrode 350 generally have a groundpotential. Therefore, the first upstream reference voltage electrode 310and the second upstream reference voltage electrode 350 can be alsoreferred to as a first upstream ground electrode and a second upstreamground electrode. Also, instead of the ground potential, other potentialbeing a reference voltage may be applied to the first upstream referencevoltage electrode 310 and the second upstream reference voltageelectrode 350.

A high negative voltage is applied to the upstream intermediateelectrode 330 disposed between the first upstream reference voltageelectrode 310 and the second upstream reference voltage electrode 350.Therefore, the upstream intermediate electrode 330 functions as asuppression electrode that suppresses intrusion of electrons into thescanning electrode device 400. Also, by providing reference voltageelectrodes both upstream and downstream of the upstream intermediateelectrode 330, an electron shielding effect due to the suppressionelectrode is enhanced. Therefore, the upstream electrode device 300 canbe referred to as a suppression electrode device having electronsuppression action with respect to the ion beam incident on the scanningelectrode device 400.

As another embodiment, a voltage higher than a voltage needed as thesuppression voltage can be applied to the upstream intermediateelectrode 330. For example, a negative voltage of tens of kV is appliedto the upstream intermediate electrode 330. For example, a voltage ofabout −30 kV to about −50 kV is applied to the upstream intermediateelectrode 330. Therefore, the upstream electrode device 300 functions asan einzel lens. Thus, the upstream intermediate electrode 330 can bealso referred to as an einzel lens electrode. Accordingly, the upstreamelectrode device 300 allows an ion beam passing through the upstreamelectrode device 300 to converge in a vertical direction and/or ahorizontal direction, and shapes the ion beam B incident into thescanning electrode device 400. As a result, the upstream electrodedevice 300 is configured as an electrode lens that has function ofshaping or adjusting a profile of the ion beam incident into thescanning electrode device 400.

An upstream surface 330 a of the upstream intermediate electrode 330 hasan arcuate shape to have a convex curved surface. Also, a downstreamsurface 350 b of the second upstream reference voltage electrode 350 hasan arcuate shape to have a concave curved surface corresponding to theupstream surface 330 a of the upstream intermediate electrode 330.Therefore, an ion beam passing through the upstream electrode device 300converges in a horizontal direction. Also, the upstream electrode device300 may have a shape such that the ion beam passing through the upstreamelectrode device 300 converges in a vertical direction, or may have ashape such that the ion beam converges in both a horizontal directionand a vertical direction.

FIGS. 18A and 18B are diagrams schematically illustrating a shape of thefirst upstream reference voltage electrode 310. FIG. 18A illustrates anappearance of the downstream surface 310 b of the first upstreamreference voltage electrode 310, and FIG. 18B illustrates across-section taken along line X-X of FIG. 18A. As illustrated, theopening 312 of the first upstream reference voltage electrode 310 has ahorizontally-elongated rectangular shape. The opening 312 is surroundedby four sides of an upper side 314, a lower side 315, a right side 316,and a left side 317.

The first upstream reference voltage electrode 310 has a pair ofaberration correctors 324 protruding from the downstream surface 310 btoward the scanning electrode device 400. The pair of aberrationcorrectors 324 are provided on upside and downside of the opening 312with the opening 312 interposed therebetween in a vertical direction.The aberration correctors 324 have, for example, a shape such that sidesfacing each other in a vertical direction with the opening 312interposed therebetween form a triangle shape or a trapezoidal shape.

By providing the aberration correctors 324, the upper side 314 and thelower side 315 of the opening 312 has a shape such that a centralportion 320 thereof protrudes toward the scanning electrode device 400.As a result, in the upper side 314 and the lower side 315 of the firstupstream reference voltage electrode 310, a thickness w₁ of the centralportion 320 in a z direction is larger than a thickness w₂ of acircumjacent portion 322. Also, the central portion 320 is a positioncorresponding to the reference trajectory Z, and the circumjacentportion 322 is a position located away from the central portion 320 in ahorizontal direction, and a position close to the right side 316 or theleft side 317.

The aberration corrector 324 partially shields a deflecting electricfield generated by the scanning electrode device 400, and reducesaberration occurring due to provision of the beam transport correctionelectrode 450 having the beam transport correction inlet electrode body454. Hereinafter, by referring to a first upstream reference voltageelectrode and a scanning electrode device according to a comparativeexample, effects due to provision of the aberration corrector 324 to thefirst upstream reference voltage electrode 310 will be represented alongwith effects of the beam transport correction electrode 450 having thebeam transport correction inlet electrode body 454.

FIGS. 19A and 19B are diagrams schematically illustrating trajectoriesof ion beams passing through a first upstream reference voltageelectrode 1310 and a scanning electrode device 1400 according to thecomparative example. The first upstream reference voltage electrode 1310according to the comparative example does not include the aberrationcorrector 324, and has an opening shape such that thicknesses of acentral portion and a circumjacent portion in a z direction along atrajectory of an ion beam are the same as each other. Also, the scanningelectrode device 1400 according to the comparative example is providedwith a beam transport correction electrode 1450 including no beamtransport correction inlet electrode body protruding toward a beamtrajectory.

FIGS. 19A and 19B illustrate trajectories in a case in which a currentvalue of a transported ion beam is relatively low, and a state in whicha transported ion beam is hard to divergence due to a negligible spacecharge effect. Therefore, the trajectories of the transported ion beamssubstantially trace the trajectories intended in the design. Both whenan ion beam passing along the reference trajectory, and even when an ionbeam passing outside of the reference trajectory, the ion beams aredeflected at the substantially same angle due to the deflecting electricfield applied by the scanning electrode. Therefore, as illustrated inFIG. 19A, ion beams passing along the central trajectory F1 and ionbeams passing along the left outer trajectory E1 and the right outertrajectory G1 with respect to the central trajectory F1 are deflected atthe substantially same angle. Also, as illustrated in FIG. 19B, ionbeams passing along the upper outer trajectory J1 and the lower outertrajectory K1 with respect to the central trajectory are transportedwhile hardly diverging in a vertical direction at all, due to thenegligible space charge effect.

Here, the “space charge effect” means to a phenomenon in which, withrespect to an ion beam including many ions with positive charge, adiameter of the ion beam is expanded in a horizontal direction, in avertical direction, or in both directions due to a repulsive forceacting between adjacent ions. In a case in which a current value of anion beam is low, since a spatial charge density of ions included in theion beam is also low and a distance between adjacent ions is spacedapart from each other, the repulsive force hardly occurs. On the otherhand, in a case in which a current value of an ion beam is high, since aspatial charge density of ions included in the ion beam is also high andadjacent ions is close to each other, a relatively strong repulsiveforce occurs, which is resulted in a state in which a beam diameter islikely to be easily expanded. Therefore, in order to appropriatelytransport a high current ion beam, there is a need to design a beamlinein consideration of the space charge effect.

A beam trajectory in a case in which a current value of a transportedion beam is relatively high will be described below. In this case, it isassumed that trajectories E1, F1, G1, J1 and K1 of an ion beamillustrated in FIGS. 19A and 19B are designed trajectories beingreferences. The designed trajectories may be trajectories for whichinfluence of the space charge effect that needs to be taken into accountin the case of transport of a high current ion beam is compensated, andmay be ideal trajectories which correspond to a target in transport of ahigh current beam.

FIGS. 20A and 20B are diagrams schematically illustrating trajectoriesof ion beams passing through the first upstream reference voltageelectrode 1310 and the scanning electrode device 1400 according to thecomparative example. In the present drawings, there are illustratedtrajectories in a case in which a current value of a transported ionbeam is relatively high in the same device configuration as FIGS. 19Aand 19B, and in a state in which the beam diverges due to the spacecharge effect in both a horizontal direction and a vertical direction.

As illustrated in FIG. 20A, an ion beam passing along a centraltrajectory F2 passes along a trajectory substantially identical to thedesigned trajectory F1 whereas ion beams passing along a right outertrajectory E2 and a left outer trajectory G2 pass along trajectoriesslightly deviated to outside from the designed trajectories E1 and G1.Also, as illustrated FIG. 20B, ion beams passing along an upper outertrajectory J2 and a lower outer trajectory K2 greatly diverge in avertical direction with respect to designed trajectories J1 and K1. Anion beam incident into the scanning electrode device 1400 stronglyconverges in a vertical direction and has a beam cross-sectional shapewhich is expanded in a horizontal direction, based on which it isconsidered that the space charge effect acts strongly in a verticaldirection.

When a diameter of the beam emitted from the scanning electrode device1400 is expanded greatly in a vertical direction as described above,this affects devices downstream from the scanning electrode device 1400.For example, when it is tried to transport an ion beam having a widebeam diameter as it is, there is a need to expand openings for ion beampassage which are provided in various electrodes, resulting in arequirement to increase a size of electrodes disposed downstream. Also,when the electrodes are sized up, capacities of power supplies thatapply high voltage to electrodes need to be increased. This results inan increase in the size of the entire apparatus and therefore, a costfor the apparatus increases.

Therefore, according to the present embodiment, the beam transportcorrection inlet electrode body 454 protruding toward a referencetrajectory is provided in the beam transport correction electrode 450,thereby causing an ion beam to converge in a vertical direction in thevicinity of the inlet of the scanning electrode device 400. FIGS. 21Aand 21B are diagrams schematically illustrating trajectories of ionbeams passing through a first upstream reference voltage electrode 1310and a scanning electrode device 400 according to an embodiment of thepresent invention. The first upstream reference voltage electrode 1310has the same configuration as the above-described comparative example,but the scanning electrode device 400 is different from that of thecomparative example in that the beam transport correction electrode 450has the beam transport correction inlet electrode body 454.

As illustrated in FIG. 21B, by providing the beam transport correctioninlet electrode body 454, it is possible to cause a beam to converge ina vertical direction in the inlet 402 of the scanning electrode device400. Therefore, in the present embodiment, ion beams passing along theupper outer and lower outer trajectories J3 and K3 is suppressed so asnot to diverge in a vertical direction, compared to the trajectories J2and K2 according to the comparative example. Thus, it is possible toprevent influence due to the phenomenon that the ion beam emitted fromthe scanning electrode device 400 is expanded in a vertical direction.

On the other hand, as illustrated in FIG. 21A, an ion beam passing alonga central trajectory F3 which is close to the beam transport correctioninlet electrode body 454 is deviated from the designed trajectory F1 dueto influence of the beam transport correction inlet electrode body 454.The reason for this is that, due to presence of the beam transportcorrection inlet electrode body 454, distortion occurs in a deflectingelectric field near the beam transport correction inlet electrode body454, and an ion passing along a trajectory is relatively stronglydeflected as the trajectory is closer to the beam transport correctioninlet electrode body 454. As a result, aberration occurs in the vicinityof the reference trajectory of an ion beam and a beam quality of an ionbeam passing through the scanning electrode device 400 is degraded.

In the present embodiment, by providing the aberration corrector 324 inthe central portion 320 of the first upstream reference voltageelectrode 310, the influence of aberration occurring in the vicinity ofa reference trajectory of an ion beam is suppressed. FIGS. 22A and 22Bare diagrams schematically illustrating trajectories of ion beamspassing through a first upstream reference voltage electrode 310 and ascanning electrode device 400 according to an embodiment of the presentinvention. As illustrated, the aberration corrector 324 is provided toprotrude toward the beam transport correction inlet electrode body 454.The aberration corrector 324 has an effect that partially shields adeflecting electric field generated by the scanning electrode device 400in the vicinity of the aberration corrector 324. As a result, withrespect to an ion beam passing along the central trajectory F4, adeflecting electric field is partially shielded by the aberrationcorrector 324 and a substantial distance over which the deflectingelectric field acts is shortened. Therefore, influence is suppressed, inwhich an ion passing along a trajectory is relatively strongly deflectedas the ion is closer to the beam transport correction inlet electrodebody 454. Thus, by providing the aberration corrector 324, it ispossible to suppress the influence of aberration occurring in thevicinity of a reference trajectory of an ion beam and improve a beamquality. The upstream electrode device 300 may be configured as anelectrode lens that has function of shaping or adjusting a profile ofthe ion beam incident on the scanning electrode device 400, inconjunction with the beam transport correction electrode 450.

FIGS. 23A and 23B are diagrams schematically illustrating trajectoriesof ion beams passing through an upstream electrode device 300 and ascanning electrode device 400 according to an embodiment of the presentinvention. The present drawings illustrate a configuration in which theupstream intermediate electrode 330 and the second upstream referencevoltage electrode 350 are added upstream of the first upstream referencevoltage electrode 310. As described above, by applying a high voltagehigher than the suppression voltage to the upstream intermediateelectrode 330, the upstream electrode device 300 functions as an einzellens. That is, the upstream electrode device 300 allows an ion beam toconverge in a horizontal direction before allowing the ion beam to beincident into the scanning electrode device 400. As illustrated in FIG.23A, this allows ion beams passing along trajectories E5 and G5 on theright outside and the left outside of a center trajectory to converge ina horizontal direction, compared to the trajectories E4 and G4 with noeinzel lens.

FIGS. 24A and 24B are diagrams schematically illustrating a shape of abeam transport correction electrode 450 according to a modification. Inthe above-described embodiment, the beam transport correction electrode450 includes the straight portion 452 extending from the inlet 402 ofthe scanning electrode device 400 to the outlet 404. As illustrated inFIG. 24A, in the beam transport correction electrode 450 according toone modification, a length of the straight portion 452 may be shortenedand the beam transport correction electrode 450 may be provided onlyupstream of the scanning electrode device 400. Also, as illustrated inFIG. 24B, in the beam transport correction electrode 450 according toanother modification, the straight portion 452 may not be provided, andthe beam transport correction electrode 450 may be configured by onlythe beam transport correction inlet electrode body 454 disposed near theinlet 402 of the scanning electrode device 400. According to themodifications, it is also possible to allow an ion beam to converge in avertical direction in the vicinity of the inlet 402 of the scanningelectrode device 400 and, at the same time, obtain an effect thatsuppresses occurrence of the zero field effect, like the above-describedembodiment.

FIG. 25 is a diagram schematically illustrating trajectories of ionbeams passing through the first upstream reference voltage electrode1310 and the scanning electrode device 400 according to anothermodification. In the above-described embodiment, as illustrated in FIG.21A, there has been described a case in which an ion beam passing alongthe central trajectory F3 close to the beam transport correction inletelectrode body 454 is strongly deflected by the influence of the beamtransport correction inlet electrode body 454. On the other hand, in thepresent modification, there is provided a case in which an ionbeampassing along a central trajectory F6 close to the beam transportcorrection inlet electrode body 454 is relatively weakly deflected bythe influence of the beam transport correction inlet electrode body 454.Depending on a shape or arrangement of the beam transport correctioninlet electrode body 454 as illustrated, a deflection strength may beweakened in the vicinity of the reference trajectory, caused by adistribution of a deflecting electric field is disturbed due to presenceof the beam transport correction inlet electrode body 454. Even in thiscase, since aberration occurs in the vicinity of the referencetrajectory of an ion beam, a beam quality of an ion beam passing throughthe scanning electrode device 400 is degraded.

In the present embodiment, by providing the aberration corrector 326having a concave shape in the central portion 320 of the first upstreamreference voltage electrode 310, the influence of aberration occurringin the vicinity of a reference trajectory of an ion beam is suppressed.FIG. 26 is a diagram schematically illustrating trajectories of ionbeams passing through the first upstream reference voltage electrode 310and the scanning electrode device 400 according to a modification. Asillustrated, the aberration corrector 326 is provided such that thecentral portion 320 is recessed with respect to the beam transportcorrection inlet electrode body 454, and includes a shape such that thedownstream surface 310 b is concave with respect to the scanningelectrode device 400. In other words, an opening shape is formed suchthat a thickness w₁₁ of the central portion 320 of the first upstreamreference voltage electrode 310 in a z direction is smaller than athickness w₁₂ of the circumjacent portion 322 in a z direction.

The aberration corrector 326 has an effect that expands an area overwhich a deflecting electric field generated by the scanning electrodedevice 400 acts, and with respect to the ion beam passing along thecentral trajectory F7, a distance over which the deflecting electricfield acts becomes longer. Therefore, influence is suppressed, in whichan ion passing along a trajectory is relatively weakly deflected as theion is closer to the beam transport correction inlet electrode body 454.Thus, according to the present modification, by providing the aberrationcorrector 326 having a concave shape, it is possible to suppress theinfluence of aberration occurring in the vicinity of a referencetrajectory of an ion beam and improve a beam quality.

Also, the first upstream reference voltage electrode 310 with theaberration correctors 324 and 326 may be used for other purposes inaddition a purpose to reduce the influence of aberration occurring dueto the beam transport correction inlet electrode body 454 of the beamtransport correction electrode 450. For example, even in a case in whichthe beam transport correction inlet electrode body 454 is not providedin the vicinity of the inlet 402 of the scanning electrode device 400,when aberration occurs in an ion beam passing along the vicinity of areference trajectory, the aberration corrector 324 or 326 may beprovided for the purpose of reducing the influence of the aberration.For example, in a case in which a deflection amount of an ion beamincident into the scanning electrode device 400 along the referencetrajectory is relatively large, the aberration corrector 324 having aconvex shape may be provided in the first upstream reference voltageelectrode 310. On the other hand, in a case in which a deflection amountof an ion beam incident into the scanning electrode device 400 along thereference trajectory is relatively small, the aberration corrector 326having a concave shape may be provided in the first upstream referencevoltage electrode 310. Also, since the amount of aberration which iscorrected by the aberration corrector 324 or 326 can be adjusted byshapes of aberration corrector 324 or 326, shapes of aberrationcorrector 324 or 326 may be determined depending on a correction amountas required.

Next, returning to FIGS. 16A and 16B, the downstream electrode device500 will be described below. Electrodes that constituting the downstreamelectrode device 500 are arranged in the order of a first downstreamreference voltage electrode 510, a first downstream intermediateelectrode 530, a second downstream reference voltage electrode 550, asecond downstream intermediate electrode 570, and a third downstreamreference voltage electrode 590 from the outlet 404 of the scanningelectrode device 400 toward a downstream direction.

The first downstream reference voltage electrode 510, the firstdownstream intermediate electrode 530, the second downstream referencevoltage electrode 550, the second downstream intermediate electrode 570,and the third downstream reference voltage electrode 590 respectivelyinclude openings 512, 532, 552, 572 and 592 for ion beam passage. In thedownstream electrode device 500, since an ion beam emitted from thescanning electrode device 400 is scanned by the scanning electrodedevice 400 in a horizontal direction, the openings 512, 532, 552, 572and 592 of the electrodes have a horizontally-elongated shape.

In each of the electrodes constituting the downstream electrode device500, the opening is formed such that an opening width thereof in ahorizontal direction is expanded wide as the electrode disposeddownstream. For example, an opening width w₄ of the first downstreamintermediate electrode 530 in a horizontal direction is larger than anopening width w₃ of the first downstream reference voltage electrode 510in a horizontal direction. In addition, an opening width w₅ of thesecond downstream reference voltage electrode 550 in a horizontaldirection is larger than an opening width w₄ of the first downstreamintermediate electrode 530 in a horizontal direction.

Except for the opening 512 of the first downstream reference voltageelectrode 510, the openings 532, 552, 572 and 592 have ahorizontally-elongated rectangular cross-sectional shape. On the otherhand, the opening 512 of the first downstream reference voltageelectrode 510 has, as illustrated in FIG. 27A (described below), across-sectional shape of which opening widths of right and left ends areexpanded in a vertical direction (y direction).

The first downstream reference voltage electrode 510, the seconddownstream reference voltage electrode 550, and the third downstreamreference voltage electrode 590 generally have a ground potential.Therefore, the first downstream reference voltage electrode 510, thesecond downstream reference voltage electrode 550, and the thirddownstream reference voltage electrode 590 can also be referred to as afirst downstream ground electrode, a second downstream ground electrode,and a third downstream ground electrode, respectively. Also, instead ofthe ground potential, other potential being a reference voltage may beapplied to each of the first downstream reference voltage electrode 510,the second downstream reference voltage electrode 550, and the thirddownstream reference voltage electrode 590.

A positive high voltage of tens of kV is applied to the first downstreamintermediate electrode 530 disposed between the first downstreamreference voltage electrode 510 and the second downstream referencevoltage electrode 550, for example, a voltage of about +30 to about +50kV is applied thereto. Therefore, the first downstream reference voltageelectrode 510, the first downstream intermediate electrode 530, and thesecond downstream reference voltage electrode 550 function as an einzellens. Thus, the first downstream intermediate electrode 530 may be alsoreferred to as an einzel lens electrode. Therefore, the first downstreamreference voltage electrode 510, the first downstream intermediateelectrode 530, and the second downstream reference voltage electrode 550allow an ion beam passing through the downstream electrode device 500 toconverge in a vertical direction and/or a horizontal direction, andshapes the ion beam passing through the downstream electrode device 500.As a result, the downstream electrode device 500 is configured as anelectrode lens that has function of shaping or adjusting a profile ofthe ion beam emitted from the scanning electrode device 400.

Also, a negative high voltage of about several kV is applied to thesecond downstream intermediate electrode 570 disposed between the seconddownstream reference voltage electrode 550 and the third downstreamreference voltage electrode 590, for example, a voltage of about −1 kVto about −10 kV is applied thereto. Therefore, the second downstreamintermediate electrode 570 functions as a suppression electrode thatsuppresses intrusion of electrons into the scanning electrode device400. Also, by providing reference voltage electrodes both upstream anddownstream of the second downstream intermediate electrode 570, anelectron shielding effect due to the suppression electrode is enhanced.Therefore, the downstream electrode device 500 can also be referred toas a suppression electrode device having electron suppression functionwith respect to the ion beam emitted from the scanning electrode device400.

FIGS. 27A and 27B are diagrams schematically illustrating a shape of thefirst downstream reference voltage electrode 510. FIG. 27A illustratesan appearance of a downstream surface 510 b of a first downstreamreference voltage electrode 510, in which a position of a scanningelectrode 410 disposed upstream of the first downstream referencevoltage electrode 510 is indicated by a dashed line. FIG. 27Billustrates X-X line cross section of FIG. 27A. As illustrated, anopening 512 of the first downstream reference voltage electrode 510substantially has a horizontally-elongated rectangular shape, of whichan opening width in a vertical direction is expanded in the vicinity ofboth right and left ends.

In the opening 512 of the first downstream reference voltage electrode510, an opening width h₂ of circumjacent portions 522R and 522L in avertical direction is larger than an opening width h₁ of a centralportion 520 corresponding to a reference trajectory Z in a verticaldirection. Also, while the opening width in a vertical direction in acentral area X1 near the central portion 520 is uniform at h₁, and theopening width in a vertical direction in a circumjacent area X2 near thecircumjacent regions 522R and 522L increases as closer to left and rightends. In this case, the circumjacent area X2 is a position facing adownstream end of the scanning electrode 410, that is a position facingdownstream ends 422R and 422L of the electrode inner surfaces 412R and412L of the scanning electrode 410.

Unlike in a position spaced apart from the electrode inner surfaces 412Rand 412L at a certain distance, electric field distribution is distortedin the vicinity of the downstream ends 422R and 422L of the scanningelectrode 410. The reason for this is that the electric fielddistribution is more disturbed in the vicinity of the ends of theelectrodes, as compared to in the vicinity of a center of the electrodesurface. Therefore, an ion beampassing through the vicinity of thedownstream ends 422R and 422L of the scanning electrode 410 is affectedby the distorted deflecting electric field, causing convergence in anunintended direction.

According to the present embodiment, in the circumjacent area X2 being aposition facing the downstream ends 422R and 422L of the scanningelectrode 410, the influence of the distorted deflecting electric fieldis reduced by expanding the opening width of the opening 512 of thefirst downstream reference voltage electrode 510 in a verticaldirection.

FIG. 28 is a diagram schematically illustrating a configuration of afirst downstream reference voltage electrode 510 and a first downstreamintermediate electrode 530. The first downstream intermediate electrode530 has an upstream surface 530 a which is perpendicular to a referencetrajectory Z and has a shape such that the upstream surface 530 aprotrudes toward the first downstream reference voltage electrode 510 inthe vicinity of the central portion 540 at which the referencetrajectory Z is disposed. Also, the first downstream intermediateelectrode 530 has an upper side 534, a lower side 535, a right side 536,and a left side 537 which surround the opening 532, and has a shape suchthat the central portion 540 of the upper side 534 and lower side 535protrude toward the first downstream reference voltage electrode 510.Therefore, in the first downstream intermediate electrode 530, athickness of the opening 532 in a z direction along the referencetrajectory Z, that is, a thickness w₇ of the central portion 540 islarger than a thickness w₈ of circumjacent portions 542R and 542L. Also,in the opening 532 of the first downstream intermediate electrode 530,the thickness w₇ in a z direction is uniform in the central area X1, andthe thickness in a z direction gradually decreases in the circumjacentarea X2, and, the thickness w₈ becomes smaller than that in the centralarea X1, outside the circumjacent area X2.

On the other hand, the downstream surface 510 b of the first downstreamreference voltage electrode 510 has a flat surface, while the downstreamsurface 510 b is perpendicular to the reference trajectory Z. That is,in the opening 512 of the first downstream reference voltage electrode510, a thickness w₆ in a z direction is uniform in both the central areaX1 and the circumjacent area X2. Therefore, as to a distance between thedownstream surface 510 b of the first downstream reference voltageelectrode 510 and the upstream surface 530 a of the first downstreamintermediate electrode 530, the distance L₁ is small in the central areaX1, the distance is gradually expanded in the circumjacent area X2, andthe distance L₂ becomes large outside the circumjacent area X2.

In the present embodiment, by making slope in a gap between the firstdownstream reference voltage electrode 510 and the first downstreamintermediate electrode 530 in the circumjacent area X2, the influence ofaberration is reduced, aberration occurring due to the fact that theopening width of the opening 512 of the first downstream referencevoltage electrode 510 is expanded in a vertical direction in thecircumjacent area X2. The downstream electrode device 500 may beconfigured as an electrode lens that corrects deflection aberrationoccurring in an ion beam emitted from the scanning electrode device 400.In particular, the downstream electrode device 500 may correctdeflection aberration occurring in an ion beam passing through thevicinity of the downstream ends 422 of the scanning electrode 410, fromamong all ion beams emitted from the scanning electrode device 400.

Hereinafter, effects caused by expanding the opening 512 of the firstdownstream reference voltage electrode 510 in a vertical direction inthe circumjacent area X2 will be described while referring to thescanning electrode device, the first downstream reference voltageelectrode and the first downstream intermediate electrode according tothe comparative example. Subsequently, in the circumjacent area X2, aneffect occurring due to the fact that slope is made in the gap betweenthe first downstream reference voltage electrode 510 and the firstdownstream intermediate electrode 530 will be described.

FIG. 29 is a diagram schematically illustrating trajectories of ionbeams passing through the scanning electrode device 400, the firstdownstream reference voltage electrode 1510, and the first downstreamintermediate electrode 1530 according to the comparative example. FIG.30 is a diagram schematically illustrating a shape of the firstdownstream reference voltage electrode 1510 according to the comparativeexample. As illustrated in FIG. 30, a shape of an opening 1512 of thefirst downstream reference voltage electrode 1510 according to thecomparative example is a rectangular shape, in which an opening width h₁in a vertical direction is uniform at a central portion 1520 andcircumjacent portions 1522R and 1522L. Also, as illustrated in FIG. 29,the central portion of the first downstream intermediate electrode 1530according to the comparative example does not protrude toward the firstdownstream reference voltage electrode 1510, and a gap between the firstdownstream reference voltage electrode 1510 and the first downstreamintermediate electrode 1530 is uniform.

In FIG. 29, ion beam trajectories E1 and G1 indicated by dashed linesrepresent a case in which a beam diameter D_(x1) in a horizontaldirection is small, and ion beam trajectories E2 and G2 indicated bysolid lines represent a case in which a beam diameter D_(x2) in ahorizontal direction is large. In a case in which a current value of anion beam is relatively low, since the influence of beam divergence dueto the space charge effect is small, it is easy to transport an ion beamwith a high beam quality, of which a cross-sectional ion distribution isuniform even in the case of reducing the beam diameter D_(x1) asindicated by the dashed lines. However, in a case in which a currentvalue of an ion beam is high, a beam easily diverges due to the spacecharge effect, and therefore, it is difficult to transport an ion beamwith the beam diameter D_(x1) that is small as indicated by the dashedlines. Therefore, it is required to adjust the beam diameter D_(x2) thatis large as indicated by the solid lines in order to transport a highcurrent ion beam.

When it is tried to transport an ion beam having the large beam diameterD_(x2) with using a device designed to transport an ion beam having thesmall beam diameter D_(x1), an ion passing through the outer side of abeam trajectory is brought close to openings end of electrodes. Sincethe electric field distributions in the vicinities of the opening endsof the electrodes are more disturbed, as compared to a center of theopening, an ion beam passing through the vicinities of the opening endsmay be deflected in an unintended direction, and/or converges in anunintended state. For example, in the case of deflecting an ion beam ina right direction, an ion beam passing along a right outer trajectory G2passes through a point Q close to a downstream end 422R of a rightscanning electrode 410R and an upstream end 1516 a of a right side 1516of the first downstream reference voltage electrode 1510. At the pointQ, disturbance in electric field distribution is large and the ion beameasily converges in a vertical direction (y direction) as compared to apoint P through which an ion beam passing along a left outer trajectoryE2 passes. Then, only an ion beam passing along the right outertrajectory G2 greatly converges in a vertical direction, and therefore,aberration occurs. Thereafter, a beam quality of a transported ion beamis degraded.

It may be considered that it is possible to prevent such a phenomenonfrom occurring by preventing an ion beam passing along an outertrajectory from passing through the vicinities of the openings of theelectrodes. However, it is required to enlarge the openings for ion beampassage which are provided in various electrodes in order to prevent anion beam from passing through the vicinities of the opening edges of theelectrodes, causing a requirement to increase sizes of electrodesdisposed downstream. In addition, when the electrodes are increased insize, capacities of a power supplies that apply a high voltages toelectrodes also need to be increased. This results in an increase in thesize of the entire apparatus and therefore, a cost for the apparatusincreases.

Therefore, in the present embodiment, the influence of theabove-described aberration is reduced by using the first downstreamreference voltage electrode 510 having an increased opening width in avertical direction in the circumjacent areas corresponding to a positionfacing the downstream end 422 of the scanning electrode 410. FIG. 31 isa diagram schematically illustrating trajectories of ion beams passingthrough the scanning electrode device 400, the first downstreamreference voltage electrode 510, and the first downstream intermediateelectrode 1530 according to an embodiment of the present invention. Thefirst downstream reference voltage electrode 510 has a shape in which anopening width of the circumjacent portion 522 in a vertical direction isexpanded, and therefore, it is possible to reduce vertical convergenceoccurring when an ion beam passing along the right outer trajectory G3passes through the point Q.

However, when the opening width of the circumjacent portion 522 of thefirst downstream reference voltage electrode 510 in vertical directionis expanded, this may cause occurrence of other aberration. When theopening shape of the first downstream reference voltage electrode 510 ischanged, similarity of the shape is diminished with respect to theopening shape of the first downstream intermediate electrode 530.Therefore, disturbance in electric field distribution occurs between thefirst downstream reference voltage electrode 510 and the firstdownstream intermediate electrode 530. In particular, when a highvoltage is applied to the first downstream intermediate electrode 530 inorder to allow the first downstream intermediate electrode 530 tofunction as an einzel lens electrode, disturbance in electric fielddistribution becomes remarkable, and only an ion beam passing throughthe vicinity of the circumjacent portion 522 of the first downstreamreference voltage electrode 510 converges in a horizontal direction,thereby other aberration occurring.

Therefore, in the present embodiment, occurrence of the above-describedother aberration is suppressed by making slope in a distance between thefirst downstream reference voltage electrode 510 and the firstdownstream intermediate electrode 530 in the circumjacent areascorresponding to a position facing the downstream end 422 of thescanning electrode 410. FIG. 32 is a diagram schematically illustratingtrajectories of ion beams passing through the scanning electrode device400, the first downstream reference voltage electrode 510, and the firstdownstream intermediate electrode 530 according to an embodiment of thepresent invention. As illustrated, the first downstream intermediateelectrode 530 has a shape in which, with respect to a distance betweenthe first downstream reference voltage electrode 510 and the firstdownstream intermediate electrode 530, a distance L₂ in the circumjacentportion 542 is longer than a distance L₁ in the central portion 540 ofthe first downstream intermediate electrode 530. Therefore, slopes aremade such that the distance between the first downstream referencevoltage electrode 510 and the first downstream intermediate electrode530 gradually lengthens toward right and left ends thereof at a positionfacing the circumjacent portion 522 of the first downstream referencevoltage electrode 510. As a result, it is possible to reduce horizontalconvergence occurring in the vicinity of the circumjacent portion 522 ofthe first downstream reference voltage electrode 510, and suppressdegradation of a beam quality with respect to an ion beam passing alongthe right outer trajectory G4.

FIG. 33 is a diagram schematically illustrating a shape of a firstdownstream reference voltage electrode 510 and a first downstreamintermediate electrode 530 according to a modification. In the firstdownstream reference voltage electrode 510 and the first downstreamintermediate electrode 530 according to the above-described embodiments,the distance L₁ in the central area X1 and the distance L₂ outside thecircumjacent area X2 become different from each other due to protrusionof the upstream surface 530 a of the first downstream intermediateelectrode 530 toward the first downstream reference voltage electrode510. On the other hand, according to the present modification, thedistance L₁ in the central area X1 is shorten and the distance L₂outside the circumjacent area X2 is lengthened due to protrusion of thedownstream surface 510 b of the first downstream reference voltageelectrode 510 toward the first downstream intermediate electrode 530.Therefore, in the first downstream reference voltage electrode 510according to the present modification, a thickness w₆ of thecircumjacent portion 522 in z direction is small and a thickness w₉ inthe central portion 520 is large. Also, among four sides surrounding theopening 512, the central portion 520 of the upper side and the lowerside has a shape protruding toward the first downstream intermediateelectrode 530. Therefore, like the above-described embodiment, it ispossible to reduce horizontal aberration occurring in an ion beampassing through the circumjacent area X2.

FIGS. 34A and 34B schematically illustrate a trajectory of ion beamspassing through an upstream electrode device 600 and a scanningelectrode device 400 according to another embodiment of the presentinvention. Unlike the upstream electrode device 300 according to theembodiment or the modification which have been described, in theupstream electrode device 600 according to the present embodiment, aconcave portion or a convex portion is not provided in a first upstreamreference voltage electrode 610. Also, a thickness w₁₀ of an opening ofthe first upstream reference voltage electrode 610 in a z direction islarge as compared to the first upstream reference voltage electrode 310according to the embodiment or the modification which have beendescribed. Hereinafter, a description for the upstream electrode device600 is given focusing on a difference between the upstream electrodedevice 600 and the upstream electrode device 300 according to theabove-described embodiment.

The upstream electrode device 600 is arranged for a purpose to support arole of the beam transport correction inlet electrode body 454 byallowing an ion beam before being incident into the scanning electrodedevice 400 to converge in a vertical direction, in a case the effect ofvertical convergence by the beam transport correction inlet electrodebody 454 of the beam transport correction electrode 450 is notsufficient. That is, the upstream electrode device 600 has a role as abeam focusing portion provided upstream of the scanning electrode device400. A high voltage that is about several times higher than thesuppression voltage required for electron shielding is applied to anupstream intermediate electrode 630 of the upstream electrode device 600in order to enhance the effect of vertical convergence.

In this case, when a high voltage is applied to the upstreamintermediate electrode 630, this may affect a deflecting electric fieldgenerated by the scanning electrode device 400. Therefore, in order tosufficiently shield the einzel field generated by the upstreamintermediate electrode 630, the thickness w₁₀ of the first upstreamreference voltage electrode 610 in a z direction is thickened. In orderto enhance the effect that shields the einzel field, it is preferablethat the thickness w₁₀ of the first upstream reference voltage electrode610 in a z direction is similar to the opening width h₁₀ of the firstupstream reference voltage electrode 610 in the vertical direction, oris larger than the opening width h₁₀. As a result, it is possible torelieve the influence on the deflecting electric field generated by thescanning electrode device 400 and allow an ion beam incident into thescanning electrode device 400 to converge in the vertical direction inadvance. Accordingly, it is possible to suppress the vertical divergenceof the ion beam emitted from the scanning electrode device 400.

FIGS. 35A, 35B, and 35C are diagrams schematically illustrating aconfiguration of an upstream electrode device 600 and a scanningelectrode device 400 according to other modifications. According to themodifications, it may be possible to provide a horizontal convergencefunction, by shaping electrode surfaces of electrodes that constitutethe upstream electrode device 600 to have arcuate shapes.

As illustrated in FIG. 35A, it may be possible to form a first focusinglens having a concave surface corresponding to a downstream surface 650b of the second upstream reference voltage electrode 650 and a convexsurface corresponding to an upstream surface 630 a of the upstreamintermediate electrode 630, and a second focusing lens having a convexsurface corresponding to a downstream surface 630 b of the upstreamintermediate electrode 630 and a concave surface corresponding to anupstream surface 610 a of the first upstream reference voltage electrode610.

As illustrated in FIG. 35B, it may be possible to form a focusing lenshaving a concave surface corresponding to a downstream surface 650 b ofthe second upstream reference voltage electrode 650 and a convex surfacecorresponding to an upstream surface 630 a of the upstream intermediateelectrode 630, and a non-lens element having flat surfaces correspondingto the downstream surface 630 b of the upstream intermediate electrode630 and the upstream surface 610 a of the first upstream referencevoltage electrode 610.

As illustrated in FIG. 35C, it may be possible to form a focusing lenshaving a concave surface corresponding to a downstream surface 650 b ofthe second upstream reference voltage electrode 650 and a convex surfacecorresponding to an upstream surface 630 a of the upstream intermediateelectrode 630, and to form a defocusing lens having a concave surfacecorresponding to the downstream surface 630 b of the upstreamintermediate electrode 630 and a convex surface corresponding to theupstream surface 610 a of the first upstream reference voltage electrode610.

Hereinafter, several aspects of the present invention will be described.

1-1. An ion implantation apparatus according to an embodiment includes ascanning unit, the scanning unit including a scanning electrode devicethat allows a deflecting electric field to act on an ion beam incidentalong a reference trajectory and scans the ion beam in a horizontaldirection perpendicular to the reference trajectory, and an upstreamelectrode device configured by a plurality of electrode bodies providedupstream of the scanning electrode device.

The scanning electrode device includes a pair of scanning electrodesprovided to face each other in the horizontal direction with thereference trajectory interposed therebetween, and a pair of beamtransport correction electrodes provided to face each other in avertical direction perpendicular to the horizontal direction with thereference trajectory interposed therebetween.

Each of the pair of beam transport correction electrodes includes a beamtransport correction inlet electrode body protruding toward thereference trajectory in the vertical direction in the vicinity of aninlet of the scanning electrode device.

1-2. Each of the beam transport correction electrode may have a straightportion extending from the inlet of the scanning electrode device to anoutlet thereof, and

each of the beam transport correction inlet electrode bodies may beprovided to protrude from the straight portion toward the referencetrajectory in the vicinity of the inlet of the scanning electrodedevice.

1-3. Each of the beam transport correction inlet electrode bodies mayhave a plate-like member of which a thickness direction is identical tothe horizontal direction.

1-4. The upstream electrode device may include a first upstreamreference voltage electrode disposed just upstream of the scanningelectrode device and having an opening through which an ion beam passes.

The first upstream reference voltage electrode may include a downstreamsurface that faces the scanning electrode device and is perpendicular tothe reference trajectory, and a pair of aberration correctors providedin the downstream surface such that the opening is interposedtherebetween in the vertical direction and has a shape protruding towardor recessed from the scanning electrode device on the downstreamsurface, and

the opening may have a thickness in a direction along the referencetrajectory in which the thickness in a central portion disposed in thevicinity of the reference trajectory is different from the thickness ofa circumjacent portion located away from the central portion in thehorizontal direction by providing the pair of aberration correctors.

1-5. Each of the pair of the aberration correctors may have a shapeprotruding toward the scanning electrode device such that sides facingeach other in a vertical direction with the opening interposedtherebetween forma triangle shape or a trapezoid shape, and

the thickness of the opening in a direction along the referencetrajectory may be determined such that the thickness in the centralportion is larger than that in the circumjacent portion.

1-6. The upstream electrode device may further include a beam focusingportion that allows an ion beam incident into the scanning electrodedevice to converge in the vertical direction and/or the horizontaldirection.

1-7. The upstream electrode device may include a second upstreamreference voltage electrode disposed upstream of the first upstreamreference voltage electrode and an upstream intermediate electrodedisposed between the first upstream reference voltage electrode and thesecond upstream reference voltage electrode.

The upstream intermediate electrode and the second upstream referencevoltage electrode may respectively have an opening for ion beam passageat a position which communicates with the first upstream referencevoltage electrode, and

the upstream intermediate electrode may receive a high voltage which isdifferent from potentials of the first upstream reference voltageelectrode and the second upstream reference voltage electrode and have afunction that allows an ion beam incident into the scanning electrodedevice to converge in the vertical direction and/or the horizontaldirection.

1-8. The upstream electrode device may be configured as an electrodelens that has function of shaping or adjusting a profile of an ion beamincident into the scanning electrode device.

1-9. The upstream electrode device may be configured as an electrodelens that has function of shaping or adjusting a profile of an ion beamincident into the scanning electrode device, in conjunction with thepair of beam transport correction electrodes.

1-10. The upstream electrode device may be configured as a suppressionelectrode device that has electron suppression function with respect toan ion beam incident into the scanning electrode device.

1-11. The scanning unit may further include a downstream electrodedevice configured by a plurality of electrode bodies disposed downstreamof the scanning electrode device.

1-12. The downstream electrode device may be configured as an electrodelens that has function of shaping or adjusting a profile of an ion beamemitted from the scanning electrode device.

1-13. The downstream electrode device may be configured as an electrodelens that has function of shaping or adjusting a profile of an ion beamemitted from the scanning electrode device, in conjunction with the beamtransport correction electrode.

1-14. The downstream electrode device may be configured as a suppressionelectrode device that has electron suppression function with respect tothe ion beam emitted from the scanning electrode device.

1-15. Pair of the beam transport correction electrodes may be configuredas correction electrodes that have function of shaping or adjusting aprofile of an ion beam passing through the scanning electrode device.

1-16. An ion implantation apparatus according to an embodiment includesa scanning unit, the scanning unit including a scanning electrode devicethat allows a deflecting electric field to act on an ion beam incidentalong a reference trajectory and scans the ion beam in a horizontaldirection perpendicular to the reference trajectory, and an upstreamelectrode device configured by a plurality of electrode bodies providedupstream of the scanning electrode device.

The upstream electrode device may include a first upstream referencevoltage electrode disposed just upstream of the scanning electrodedevice and having an opening through which an ion beam passes,

the first upstream reference voltage electrode may include a downstreamsurface that faces the scanning electrode device and is perpendicular tothe reference trajectory, and a pair of aberration correctors providedin the downstream surface such that the opening is interposedtherebetween in a vertical direction perpendicular to the horizontaldirection and has a shape protruding toward or recessed from thescanning electrode device on the downstream surface, and

the opening may have a thickness in a direction along the referencetrajectory in which the thickness in a central portion disposed in thevicinity of the reference trajectory is different from the thickness ofa circumjacent portion located away from the central portion in thehorizontal direction by providing the pair of aberration correctors.

2-1. An ion implantation apparatus according to an embodiment includes ascanning unit, the scanning unit including a scanning electrode devicethat allows a deflecting electric field to act on an ion beam incidentalong a reference trajectory and scans the ion beam in a horizontaldirection perpendicular to the reference trajectory, and a downstreamelectrode device disposed downstream of the scanning electrode deviceand provided with openings through which the ion beam scanned in thehorizontal direction passes.

The scanning electrode device has a pair of scanning electrode providedto face each other in the horizontal direction with the referencetrajectory disposed therebetween, and

the downstream electrode device includes an electrode body configuredsuch that, with respect to an opening width in a vertical directionperpendicular to both the reference trajectory and the horizontaldirection and/or an opening thickness in a direction along the referencetrajectory, the opening width and/or the opening thickness in a centralportion in which the reference trajectory is disposed is different fromthe opening width and/or the opening thickness in the vicinity of aposition facing the downstream end of the scanning electrode.

2-2. The downstream electrode device may be configured as an electrodelens that corrects deflected aberration occurring in an ion beam emittedfrom the scanning electrode device, as a result of scanning deflectionby the scanning electrode device.

2-3. The downstream electrode device may be configured as an electrodelens that corrects deflected aberration occurring in an ion beam passingthrough the vicinity of both scanning ends from among ion beams emittedfrom the scanning electrode device, as a result of scanning deflectiondue to the scanning electrode device.

2-4. The downstream electrode device may include a first downstreamreference voltage electrode disposed just downstream of the scanningelectrode device, and

the opening of the first downstream reference voltage electrode may havean opening width in which the opening width in the vertical direction inthe vicinity of a position facing the downstream end of the scanningelectrode device is larger than the opening width in the verticaldirection in the central portion in which the reference trajectory isdisposed.

2-5. The opening of the first downstream reference voltage electrode mayhave an opening width such that the opening width in the verticaldirection is uniform in the vicinity of the central portion and theopening width in the vertical direction increases toward right and leftends of the opening in the vicinity of a position facing the downstreamend of the scanning electrode.

2-6. The downstream electrode device may further include a seconddownstream reference voltage electrode disposed downstream of the firstdownstream reference voltage electrode and a first downstreamintermediate electrode disposed between the first downstream referencevoltage electrode and the second downstream reference voltage electrode.

The first downstream intermediate electrode and the second downstreamreference voltage electrode may respectively have an opening for ionbeam passage at a position which communicates with the first downstreamreference voltage electrode,

the first downstream intermediate electrode may receive a high voltageof which a potential is different from that of the first downstreamreference voltage electrode and the second downstream reference voltageelectrode,

the first downstream reference voltage electrode may have a downstreamsurface facing the first downstream intermediate electrode andperpendicular to the reference trajectory,

the first downstream intermediate electrode may have an upstream surfacefacing the first downstream reference voltage electrode andperpendicular to the reference trajectory, and

the first downstream reference voltage electrode and the firstdownstream intermediate electrode may have a shape such that withrespect to a distance between the downstream surface of the firstdownstream reference voltage electrode and the upstream surface of thefirst downstream intermediate electrode, the distance in the vicinity ofa position facing the downstream end of the scanning electrode is largerthan the distance in the central portion in which the referencetrajectory is disposed.

2-7. The first downstream reference voltage electrode and the firstdownstream intermediate electrode may be configured such that thedistance between the downstream surface of the first downstreamreference voltage electrode and the upstream surface of the firstdownstream intermediate electrode gradually increases toward right andleft ends of the opening in the vicinity of a position facing thedownstream end of the scanning electrode.

2-8. The upstream surface of the first downstream intermediate electrodemay have a shape protruding toward the first downstream referencevoltage electrode in the vicinity of the central portion in which thereference trajectory is disposed.

2-9. The downstream surface of the first downstream reference voltageelectrode may have a shape protruding toward the first downstreamintermediate electrode in the vicinity of the central portion in whichthe reference trajectory is disposed.

2-10. The opening of the first downstream intermediate electrode mayhave an opening width in the horizontal direction which is larger thanan opening width in the horizontal direction of the first downstreamreference voltage electrode, and

the opening of the second downstream reference voltage electrode mayhave an opening width in the horizontal direction which is larger thanan opening width in the horizontal direction of the first downstreamintermediate electrode.

2-11. The downstream electrode device may further include a thirddownstream reference voltage electrode disposed downstream of the seconddownstream reference voltage electrode and a second downstreamintermediate electrode disposed between the second downstream referencevoltage electrode and the third downstream reference voltage electrode,

the second downstream intermediate electrode and the third downstreamreference voltage electrode may respectively have an opening for ionbeam passage at a position which communicates with the second downstreamreference voltage electrode, and

the second downstream intermediate electrode may receive a high voltageof which a potential is different from a potential of the seconddownstream reference voltage electrode and the third downstreamreference voltage electrode and have a function that suppressesintrusion of electrons into the scanning electrode device.

2-12. The first downstream intermediate electrode may receive a highvoltage of which an absolute value is larger than a potential of thesecond downstream intermediate electrode, and have a function thatallows an ion beam emitted from the scanning electrode device toconverge in the vertical direction and/or the horizontal direction.

2-13. The scanning unit may further include an upstream electrode deviceconfigured by a plurality of electrode bodies provided upstream of thescanning electrode device.

2-14. The upstream electrode device may have function of shaping oradjusting a profile of an ion beam incident into the scanning electrodedevice.

2-15. The upstream electrode device may be configured as a suppressionelectrode device having electron suppression function with respect to anion beam incident into the scanning electrode device.

2-16. The scanning electrode device may include a pair of scanningelectrodes provided to face each other in the horizontal direction withthe reference trajectory interposed therebetween, and a pair of beamtransport correction electrodes provided to face each other in thevertical direction with the reference trajectory interposedtherebetween, and

the beam transport correction electrode is configured as a correctionelectrode that have a shaping function or an adjusting function withrespect to a beam shape of an ion beam passing through the scanningelectrode device.

2-17. The scanning electrode device may include a pair of scanningelectrodes provided to face each other in the horizontal direction withthe reference trajectory interposed therebetween, and a pair of beamtransport correction electrodes provided to face each other in thevertical direction with the reference trajectory interposedtherebetween, and

the downstream electrode device is configured as an electrode lens thathave a shaping function or an adjusting function with respect to a beamshape of an ion beam passing through the scanning electrode device inconjunction with the upstream electrode device and the beam transportcorrection electrode.

What is claimed is:
 1. An ion implantation apparatus including ascanning unit, the scanning unit comprising: a scanning electrode devicethat allows a deflecting electric field to act on an ion beam incidentalong a reference trajectory and scans the ion beam in a horizontaldirection perpendicular to the reference trajectory, and a downstreamelectrode device disposed downstream of the scanning electrode deviceand provided with openings through which the ion beam scanned in thehorizontal direction passes, wherein the scanning electrode deviceincludes a pair of scanning electrodes disposed to face each other inthe horizontal direction with the reference trajectory interposedtherebetween, and the downstream electrode device includes an electrodebody configured such that, with respect to an opening width in avertical direction perpendicular to both the reference trajectory andthe horizontal direction and/or an opening thickness in a directionalong the reference trajectory, the opening width and/or the openingthickness in a central portion in which the reference trajectory isdisposed is different from the opening width and/or the openingthickness in the vicinity of a position facing a downstream end of thescanning electrode.
 2. The ion implantation apparatus according to claim1, wherein the downstream electrode device is configured as an electrodelens that corrects deflection aberration occurring in an ion beamemitted from the scanning electrode device, as a result of scanningdeflection by the scanning electrode device.
 3. The ion implantationapparatus according to claim 1, wherein the downstream electrode deviceis configured as an electrode lens that corrects deflection aberrationoccurring in an ion beam passing through the vicinity of both scanningends from among ion beams emitted from the scanning electrode device, asa result of scanning deflection by the scanning electrode device.
 4. Theion implantation apparatus according to claim 1, wherein the downstreamelectrode device includes a first downstream reference voltage electrodedisposed just downstream of the scanning electrode device, and theopening of the first downstream reference voltage electrode has anopening width such that the opening width in the vertical direction inthe vicinity of a position facing the downstream end of the scanningelectrode device is larger than the opening width in the verticaldirection in the central portion in which the reference trajectory isdisposed.
 5. The ion implantation apparatus according to claim 4,wherein the opening of the first downstream reference voltage electrodehas an opening width such that the opening width in the verticaldirection is uniform in the vicinity of the central portion, and theopening width in the vertical direction gradually increases toward rightand left ends of the opening in the vicinity of a position facing thedownstream end of the scanning electrode.
 6. The ion implantationapparatus according to claim 4, wherein the downstream electrode devicefurther includes a second downstream reference voltage electrodedisposed downstream of the first downstream reference voltage electrodeand a first downstream intermediate electrode disposed between the firstdownstream reference voltage electrode and the second downstreamreference voltage electrode, the first downstream intermediate electrodeand the second downstream reference voltage electrode respectively havean opening for ion beam passage at a position which communicates withthe opening of the first downstream reference voltage electrode, thefirst downstream intermediate electrode receives a high voltage of whicha potential is different from potentials of the first downstreamreference voltage electrode and the second downstream reference voltageelectrode, the first downstream reference voltage electrode has adownstream surface facing the first downstream intermediate electrodeand perpendicular to the reference trajectory, the first downstreamintermediate electrode has an upstream surface facing the firstdownstream reference voltage electrode and perpendicular to thereference trajectory, and the first downstream reference voltageelectrode and the first downstream intermediate electrode have a shapesuch that with respect to a distance between the downstream surface ofthe first downstream reference voltage electrode and the upstreamsurface of the first downstream intermediate electrode, the distance inthe vicinity of a position facing the downstream end of the scanningelectrode is larger than the distance in the central portion in whichthe reference trajectory is disposed.
 7. The ion implantation apparatusaccording to claim 6, wherein the first downstream reference voltageelectrode and the first downstream intermediate electrode are configuredsuch that a distance between the downstream surface of the firstdownstream reference voltage electrode and the upstream surface of thefirst downstream intermediate electrode gradually increases toward rightand left ends of the opening in the vicinity of a position facing thedownstream end of the scanning electrode.
 8. The ion implantationapparatus according to claim 6, wherein the upstream surface of thefirst downstream intermediate electrode has a shape protruding towardthe first downstream reference voltage electrode in the vicinity of thecentral portion in which the reference trajectory is disposed.
 9. Theion implantation apparatus according to claim 6, wherein the downstreamsurface of the first downstream reference voltage electrode has a shapeprotruding toward the first downstream intermediate electrode in thevicinity of the central portion in which the reference trajectory isdisposed.
 10. The ion implantation apparatus according to claim 6,wherein the opening of the first downstream intermediate electrode hasan opening width in the horizontal direction which is larger than anopening width in the horizontal direction of the first downstreamreference voltage electrode, and an opening of the second downstreamreference voltage electrode has an opening width in the horizontaldirection which is larger than an opening width in the horizontaldirection of the first downstream intermediate electrode.
 11. The ionimplantation apparatus according to claim 6, wherein the downstreamelectrode device further includes a third downstream reference voltageelectrode disposed downstream of the second downstream reference voltageelectrode and a second downstream intermediate electrode disposedbetween the second downstream reference voltage electrode and the thirddownstream reference voltage electrode, the second downstreamintermediate electrode and the third downstream reference voltageelectrode respectively have an opening for ion beam passage at aposition which communicates with the opening of the second downstreamreference voltage electrode, and the second downstream intermediateelectrode receives a high voltage of which a potential is different frompotentials of the second downstream reference voltage electrode and thethird downstream reference voltage electrode, and has a function thatsuppresses intrusion of electrons into the scanning electrode device.12. The ion implantation apparatus according to claim 11, wherein thefirst downstream intermediate electrode receives a high voltage of whichan absolute value is larger than an absolute value of a potential of thesecond downstream intermediate electrode, and has a function that allowsan ion beam emitted from the scanning electrode device to converge inthe vertical direction and/or the horizontal direction.
 13. The ionimplantation apparatus according to claim 1, wherein the scanning unitfurther includes an upstream electrode device configured by a pluralityof electrode bodies provided upstream of the scanning electrode device.14. The ion implantation apparatus according to claim 13, wherein theupstream electrode device is configured as an electrode lens that hasfunction of shaping or adjusting a profile of an ion beam incident intothe scanning electrode device.
 15. The ion implantation apparatusaccording to claim 13, wherein the upstream electrode device isconfigured as a suppression electrode device having electron suppressionfunction with respect to an ion beam incident into the scanningelectrode device.
 16. The ion implantation apparatus according to claim1, wherein the scanning electrode device includes a pair of scanningelectrodes provided to face each other in the horizontal direction withthe reference trajectory interposed therebetween, and a pair of beamtransport correction electrodes provided to face each other in thevertical direction with the reference trajectory interposedtherebetween, and the beam transport correction electrode is configuredas a correction electrode that has shaping function or adjustingfunction with respect to a beam shape of an ion beam passing through thescanning electrode device.
 17. The ion implantation apparatus accordingto claim 13, wherein the scanning electrode device includes a pair ofscanning electrodes provided to face each other in the horizontaldirection with the reference trajectory interposed therebetween, and apair of beam transport correction electrodes provided to face each otherin the vertical direction with the reference trajectory interposedtherebetween, and the downstream electrode device is configured as anelectrode lens that has shaping function or adjusting function withrespect to a beam shape of an ion beam emitted from the scanningelectrode device, in conjunction with the upstream electrode device andthe beam transport correction electrodes.